Logo
Please visit our Sponsors
FAQs about Ariid Catfishes, aka Columbian, Silver-Tipped-... "Sharks" Systems

Related Articles: Marine, Brackish & Freshwater Catfishes (Columbian, Silver-Tipped, Black Fin... "Sharks") of the Family Ariidae by Bob Fenner, Columbian Shark Catfishes and other Ariidae by Neale Monks,

Related FAQs: Ariid Cats 1, Ariid Cats 2, Ariid ID, Ariid Behavior, Ariid Compatibility, Ariid Selection, Ariid Feeding, Ariid Disease, Ariid Reproduction, Marine Catfishes, Catfishes in General

.Large, well circulated, filter systems of.. hard, alkaline water at least as juveniles... if not brackish... to full marine with growth, age

Columbian shark (silver tip catfish); stkg., sys.         9/6/15
Hi I have recently fell for the Columbian sharks and despite all the effort to keep them for years on end I am determined to keep them. I purchased 2 juveniles currently about 3 inches long they are in a freshwater aquarium at this current moment but I am in the process of picking up 2 more juveniles and a larger tank intended to be just for them.
<Glad you're getting more than two. These catfish really are happy in groups. They will thrive in hard, alkaline freshwater for many months, but as you appreciate need brackish or marine conditions eventually.>

I am wondering how to set up the tank properly and also how much time I have to get them into their brackish environment before anything happens to them
<In short, if they're less than 3-4 inches in length, they'll be fine in hard, alkaline freshwater. The harder the better. Soft water is not acceptable for long. Provided they're swimming about happily and feeding greedily they're doing okay. But at some point you'll notice them "treading water", often close to the filter outlet. This is highly suggestive of fish trying to swim towards a stronger current like a big river, and is usually thought of as their migratory instinct. This is the time to make sure
they're in brackish water. Doesn't have to be wildly brackish at this point, SG 1.003-1.005 is fine. Then, every couple of months you can up the salinity a bit as needed, to at least 1.005 and ideally something closer to 1.010. There's a good argument for moving them into marine conditions eventually as they work nicely in FOWLR systems and the various marine fish kept in them, such as Snowflake Eels, Damsels and Wrasse. Of course they also work well in regular brackish systems with Scats, Monos, Archers, Sleeper Gobies, and various other oddball fish.>
currently they are housed in a 30 gallon tank just them and a very small clown Pleco
<If he's very small, he's dinner.>
and I also was hoping you could inform me of any signs to look for on their swimming patterns or actions that would indicate that something is wrong with them
<See above. Treading water implies they want more space, more current, more salinity, or some combination of these.>
your help would be greatly appreciated none of them places who sell these fish know anything about them aside from their cost
<Do have a read here:
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/ariidae.html
http://www.wetwebmedia.com/ariidcats.htm
And follow the links on those pages. These catfish are very peaceful, very easy to keep, and very beautiful. I can't think of a single fish more like a shark than these cats, yet unlike real sharks they're hardy and low-maintenance. Cheers, Neale.>

Re: Columbian Shark Catfish; hlth., sys.         9/8/15
Hi Neale,
I wondered if you could take a look at these pictures and tell me if I he white spots and face of my smaller cat shark seem something more than scratches from the ornaments in the tank?....
<Nope, scratches from the ornaments and/or gravel. While nothing to be overly worried about, smooth gravel, ideally a fair amount of marine aquarium sand mixed in, makes a better substrate. In any case, raising the salinity will usually eliminate parasites (which I don't think these are) and even mild brackish water tends to keep Finrot and Fungus at bay except in the worst cases. As an aside, when kept in marine conditions, lowering the salinity works just as well for eliminating marine parasites.>
Also, my bigger one does this thing where he stares at me treading water than open and closes his mouth like in the photo...seems ok, right?
<Well, common behaviour anyway. Shark Cats are migratory. They're actually amazing fish for lots of reasons, for example, did you know some scientists believe that they use a primitive sort of echolocation like dolphins? To be fair others argue that they make these low level sounds for communication instead. Either way, it's cool. But my point is that these fish have a lot
more going on inside them than the average aquarium fish! Strong water currents are important to their psychological well being otherwise they go "stir crazy". Adding one or two powerheads or internal filters is a great way to boost the water current and make the tank more exciting. Make it so the fish don't have just one place with moving water. Adding companions of their own kind (which you're doing) and even other fish (such as Monos) that keep them on their toes will help. Saltwater fishermen consider Shark Cats "bait stealers". These are fish with intense curiosity and insatiable appetites, moving in and out of rivers all day (and night) and never for a moment just sitting there doing nothing. When I was in Belize I watched them mooching about the canal at the end of the hotel garden begging for food, but at the same time anything that moved suddenly would send them down into the depths. If it isn't obvious, I absolutely adore these catfish, and would encourage you to spend a little time online learning about the Ariidae generally to better keep, and more thoroughly enjoy,
these catfish as pets. Cheers, Neale.>
Re: Columbian Shark Catfish        9/8/15

So, SO glad to have found you. The "Expert" at That Fish Place in Lancaster, PA (they are supposed to be all that) tried convincing me that while they may do better in marine, they can completely adapt to freshwater, just as their "Mollie's" have done. He embarrassed me quite a bit I front of other customers, so conceded. I was increasing the salinity slowly, but as a result, began to decrease to obtain a freshwater habitat again. Well, he's wrong. Period. These guys started acting exactly as you've shared on your site. They most definitely need salt. Thank you!!
<Glad to help. All the best, Neale.>

 

shark question, the Ariid Catfish, other FW "shark" stkg./sel.    8/19/20
Hi.  Boy have I learned via this site not to purchase Black Fin Sharks from Wal-Mart.  My son fell in love with those particular animals for his 5.5 gallon tank
<Much too small>
however we are now seriously backtracking.  Is there some type of fish out there that will live happily in fresh water, not brackish, that actually resembles a shark and will be content in a small tank? 
<Not really, no>
His heart is set on some type of "shark."  Just fyi, I just formally complained to our local Wal-Mart manager about the poor maintenance of their tanks!  Thank You!  Laura Smith
<Thank you Laura... Do please read here; and or have your son read here if he's old enough to understand:
http://www.wetwebmedia.com/FWSubWebIndex/stkgSmFWSysF.htm
Bob Fenner>
Re: shark question   8/19/20

I'm so glad that I found this site before purchasing the sharks!  He will be so disappointed!
<Much more and worse so if the organisms damaged/killed one another and died>
  However we take care of all of God's nature and would never want to put something so inappropriate in a 5 gallon tank!  We will take a visit to the local specialty fish store and will make a better choice. Thanks!  Laura
<Welcome. BobF>

Columbian Sharks, sys.     12/26/11
I'm in need of advise about my Columbian sharks.
<Sure thing.>
To provide you with background of the situation, the sharks are kept in a 55 gallon tank right now with aquarium salt added to the water
<The tank size is okay for maybe a year. But these catfish do get rather large, at least 20 cm/8 inches, and they also expect lots of swimming space and a very strong current. They're migratory fish, and obviously don't like small aquaria. You'll see them "pacing" in one corner of the tank, often nearest the filter outlet. So a big tank, not too much clutter at the bottom, and a turnover rate of at least 8 times the volume of the tank and ideally 10-12 times is what you're after (e.g., for a 55 gallon tank, install filters providing turnover rates of 10 x 55 = 550 gallons/hour). Next up, salinity. Aquarium salt is the stuff used to treat Whitespot. What you need is marine aquarium salt, with a salinity of not less than SG 1.003 now, rising to around 1.010 across the next 3-6 months. SG 1.003 is roughly 6 grammes of marine aquarium salt per litre, or 0.8 oz per US gallon. You can download and use my BrackCalc application to work out the higher salinities yourself. Use a hydrometer to double check you've done things right.>
I feed them small meals twice a day but I haven't seen them eat and I'm getting nervous.
<They won't settle until their environment is right. Do understand these are big, predatory, schooling fish that ultimately need to a marine aquarium, or at least a high salinity, SG 1.010 or above. Your best approach is to keep three specimens, and plan on setting up a fish-only with live rock marine aquarium within the next year. Colombian Sharks make good companions for big but peaceful marine fish such as Lionfish, Morays, some of the Damselfish and Clownfish, Surgeonfish, and so on.>
I've tried Google and have had mixed answers so I was hoping you could help me with the feeding habits of these fish thank you
<Do read:
http://www.wetwebmedia.com/BrackishSubWebIndex/BrackishSubWebIndex.htm
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/ariidae.html
Cheers, Neale.>
Re: Columbian Sharks   12/27/11

Thank you for the advice it has helped. I moved the filters over closer to the corner and now they are swimming thru out the tank, and I'm thinking of buys a wave maker. After looking at some of the wave makers, I'm wondering how many do I need for a 55 gallon and where would I place them in the tank to best benefit the Columbian Sharks. Please understand that the 55 gallon tank is only temporary until I can get all the equipment needed for my 240 gallon to make it a marine tank.
<Do read here, re: marine wave makers:
http://www.wetwebmedia.com/ca/volume_2/cav2i5/wavemakers/Wavemakers.htm
http://www.wetwebmedia.com/WaveMkrChtJames.htm
I don't think these would be essential by any means, but one or two Koralia powerheads or similar would provide useful extra water current around the tank. There's no ideal situation for them, but dotting them around the tank so there was strong water current all around would be good. Add large rocks or bogwood roots to create more sheltered resting spots. Essentially treat as you would any large catfish, but at the same time, plan ahead for a marine-type aquarium. Most people who keep these cats do eventually create at least a basic, FOWLR system so they can keep marine fish with them.
Being invertebrate-eaters, they can't be kept with shrimps and crabs, but snails, starfish, and even corals/polyps can work.
http://www.wetwebmedia.com/fishonsetup.htm
Of course you don't have to keep them in a marine system, and medium to high salinity and filtration are the two "make or break" considerations.
Cheers, Neale.>

Black fin sharks and Pictus cat fish    5/21/11
Hi my name is Jennifer and I have a few quick questions that I'm sure you have answered but I can't seem to find it. I have a 50 gal fresh water tank with 4 black fin sharks
<Are these Sciades seemanni, the Colombian Shark Catfish? This is a brackish to marine species with no long term future in this aquarium. If we're talking about Balantiocheilos melanopterus, the Bala Shark, then that's a very large freshwater species that needs an aquarium at least twice, and realistically 3-4 times, the size of the one you have. Do read up on the needs of these fish:
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/ariidae.html
http://www.wetwebmedia.com/fwsubwebindex/bala_sharks.htm
>
and 2 Pictus cat fish a Pleco a few gold fish (they were our starter fish) and some rosie barbs oh and 2 blue Gourami.
<This is an extremely heavily stocked aquarium. You will need to thin out your fish collection soon.>
The sharks and catfish are fine until its feeding. time the swim in circles n act like they can't see the food. Now I heard the sharks have poor eye sight.
<Balantiocheilos melanopterus, the Bala Shark, has excellent eyesight and hunts by sight. So there's no reason for this species to behave in this way unless it's stressed or sick. Sciades seemanni, the Colombian Shark Catfish, by contrast, are nocturnal fish that hunt primarily by "smell" sing their whiskers, much like any other predatory catfish.>
And one if the catfish hides in the cave we have. Is that normal ? We also have put aquarium salt in the water as requested by our salesmen.
<"Aquarium salt" is not what you need here. You need a minimum of SG 1.005 at 25 C for Sciades seemanni. That's about 9 grammes of marine aquarium salt mix per litre of water. This salinity will kill all your other livestock. Obviously Sciades seemanni is not compatible with your other fish and needs its own tank. Unfortunately a lot of people buy fish without reading up on their needs first, and they wind up in precisely this sort of pickle. That's why we tell people AGAIN and AGAIN to read up on a fish first, and ideally, buy their own aquarium fish book to take shopping with them. Retailers will sometimes say any old thing to make a sale -- but then, that shouldn't surprise you.>
And if the sharks need to be in a marine environment then why do they tell you they are fresh water?
<Yes, the sharks need brackish to marine. There's an old adage that says that a fool and his money are quickly parted. It's one of the most accurate summations of retail on the planet. What I mean is that "they" tell people this because they know most shoppers are ignorant, i.e., don't bother researching about their potential pets before buying them. So "they" get away with it. Most of this sold this way wind up dead through poor care.
Yes, this drives me absolutely nuts, but here I am, trying my best to undo the damage. In any case, Sciades seemanni is a superb species and not difficult to maintain in a proper brackish to marine aquarium.>
Thanks again
Jennifer
<Happy to help. Cheers, Neale.>
Re: Black fin sharks and Pictus cat fish   5/22/11

Neale thanks for the quick response
<No problems.>
yes they are the cat fish sharks and I do agree that we should have done our research it just boggles me that they sell them in in fresh
<Caveat emptor is, in the UK and I guess the US too, the golden rule of capitalism -- "buyer beware".>
it sounds like we are going to convert we have a 20 gal tank as well so would the fresh water fish be fine in that one?
<Do read the articles mention re: the adult sizes of the Bala Sharks and Colombian Shark Catfish. Both need tanks 100+ gallons in all seriousness.
Rosy Barbs are fairly big, and they're subtropical fish as well, so you need a coolish sort of aquarium big enough for a fish that'll easily reach 10 cm/4 inches, and potentially a bit bigger, so I'd say 200 litres/55 gallons for them.>
And what's a easy way to convert the sharks n catfish?. Or do the catfish stay fresh water.
<Not sure what you mean here. Colombian Shark Catfish can be adapted to brackish or saltwater conditions easily using some version of the "drip method" -- put them into a large bucket with water at the original salinity, and across an hour, change the water in the bucket a pint at a time every 5-10 minutes until the salinity in the bucket matches the new aquarium's salinity. No point adapting them to freshwater because they won't stay healthy in that for long. As for the Bala Sharks, they're freshwater fish pure and simple.>
Thanks again
Jennifer
<Cheers, Neale.>

Black fin sharks and Pictus cat fish    5/21/11
Hi my name is Jennifer and I have a few quick questions that I'm sure you have answered but I can't seem to find it. I have a 50 gal fresh water tank with 4 black fin sharks
<Are these Sciades seemanni, the Colombian Shark Catfish? This is a brackish to marine species with no long term future in this aquarium. If we're talking about Balantiocheilos melanopterus, the Bala Shark, then that's a very large freshwater species that needs an aquarium at least twice, and realistically 3-4 times, the size of the one you have. Do read up on the needs of these fish:
http://www.wetwebmedia.com/ca/volume_7/volume_7_1/ariidae.html
http://www.wetwebmedia.com/fwsubwebindex/bala_sharks.htm
>
and 2 Pictus cat fish a Pleco a few gold fish (they were our starter fish) and some rosie barbs oh and 2 blue Gourami.
<This is an extremely heavily stocked aquarium. You will need to thin out your fish collection soon.>
The sharks and catfish are fine until its feeding. time the swim in circles n act like they can't see the food. Now I heard the sharks have poor eye sight.
<Balantiocheilos melanopterus, the Bala Shark, has excellent eyesight and hunts by sight. So there's no reason for this species to behave in this way unless it's stressed or sick. Sciades seemanni, the Colombian Shark Catfish, by contrast, are nocturnal fish that hunt primarily by "smell" sing their whiskers, much like any other predatory catfish.>
And one if the catfish hides in the cave we have. Is that normal ? We also have put aquarium salt in the water as requested by our salesmen.
<"Aquarium salt" is not what you need here. You need a minimum of SG 1.005 at 25 C for Sciades seemanni. That's about 9 grammes of marine aquarium salt mix per litre of water. This salinity will kill all your other livestock. Obviously Sciades seemanni is not compatible with your other fish and needs its own tank. Unfortunately a lot of people buy fish without reading up on their needs first, and they wind up in precisely this sort of pickle. That's why we tell people AGAIN and AGAIN to read up on a fish first, and ideally, buy their own aquarium fish book to take shopping with them. Retailers will sometimes say any old thing to make a sale -- but then, that shouldn't surprise you.>
And if the sharks need to be in a marine environment then why do they tell you they are fresh water?
<Yes, the sharks need brackish to marine. There's an old adage that says that a fool and his money are quickly parted. It's one of the most accurate summations of retail on the planet. What I mean is that "they" tell people this because they know most shoppers are ignorant, i.e., don't bother researching about their potential pets before buying them. So "they" get away with it. Most of this sold this way wind up dead through poor care.
Yes, this drives me absolutely nuts, but here I am, trying my best to undo the damage. In any case, Sciades seemanni is a superb species and not difficult to maintain in a proper brackish to marine aquarium.>
Thanks again
Jennifer
<Happy to help. Cheers, Neale.>

Sciades seemanni and Mono Questions. Acclim. to BR from FW  -- 3/3/10
I currently have a 125 gal marine tank with 2 lionfish, a snowflake eel, and one Sciades seemanni Columbian Cat.
<Mmm, this last is a social animal. Much happier w/ some of its own kind>
I almost bought a trigger until I read that the triggers hate the cats clicking noises. I am contemplating selling all bought <but?> the cat and converting to a brackish environment. I read that the cats do better in groups.
<Many species do>
My current cat is 7 to 8 inches. I want to get 1 or 2 more but cannot find them large enough. If I buy a 2 or 3 inch cat, will the larger one be aggressive toward it?
<Not likely, no>
My second question is about acclimation. I wish to add Mono argenteus and Sebae but these are almost always sold in freshwater. I was told that you can almost take them directly from fresh and put them into a marine environment. Is this true?
<Yes>
Can I do the same with archers and the cat?
<To a lesser extent, weeks instead of days, yes>
Or am I safer to set up another tank to slowly convert them to marine or brackish? Thanks for the help!
<This last is a much safer, better approach. Bob Fenner>
Re: Sciades seemanni and Mono Questions, more re acclim. to SW, impt. notes re Toxotids, ID and sys.
Hi Bob,
<Neale>
I just saw your reply to one brackish one about monos and catfish.
<Yes... responded as it was over a "day" back/old>
Would just add this: You are quite right that (subadult to adult) Sciades catfish and (any age) Monodactylus can be converted to marine conditions quickly. I'd use the drip method across an hour, as if they were swimming through an estuary, but yes, you could in theory dump them straight in.
<Ahh, please do send your input to the querior as well>
But Archers are a whole other kettle of fish. There are three species in the trade, each equally widely sold, and one of them is a freshwater to low-end brackish species, Toxotes microlepis.
<Rare in the U.S.>
It will die kept in marine conditions for any length of time. Frankly, it's unhappy above about SG 1.005. The other two species, T. chatareus and T. jaculatrix, will tolerate marine conditions though they're best kept around SG 1.010.
<Definitely send this along as well>
Diagnosing the three Archer species is tricky, but there are some drawings that should help on my web site, here:
http://homepage.mac.com/nmonks/Projects/FAQ/3c.html
Cheers, Neale
<Thank you. BobF>
Sciades seemanni and Mono Questions
<<By way of a follow-up to Bob's reply. I would just add this: Bob is quite right that (subadult to adult) Sciades catfish and (any age) Monodactylus can be converted to marine conditions quickly. I'd use the drip method across an hour, as if they were swimming through an estuary, but yes, you could in theory dump them straight in. But Archers are a whole other kettle of fish. There are three species in the trade, each equally widely sold, and one of them is a freshwater to low-end brackish species, Toxotes microlepis. It will die kept in marine conditions for any length of time.
Frankly, it's unhappy above about SG 1.005. The other two species, T. chatareus and T. jaculatrix, will tolerate marine conditions though they're best kept around SG 1.010. Diagnosing the three Archer species is tricky,
but there are some drawings that should help on my web site, here:
http://homepage.mac.com/nmonks/Projects/FAQ/3c.html
Bob believes that Toxotes microlepis rare in the US market, but German author Frank Schaefer argues it is the most widely traded. My own experience is that all three species occur roughly as often as each other,
and I've seen specimens of all three species on both sides of the Atlantic.
So do check which Archerfish you have before acclimating them to saltwater conditions. Cheers, Neale>>
Re: Sciades seemanni and Mono Questions 3/3/10

You both gave me great info. Thank you.
<You're welcome.>
The next step is convincing my wife to let me get rid of the lions and eel and replace them with monos...she likes the salt water fish more than I do lol!
<Why not keep the Lionfish and the Eel, add the Catfish and the Monos, and rehome the Archerfish? Cheers, Neale.>
Sciades seemanni and Mono Questions. Acclim. to BR from FW  -- 3/3/10

I currently have a 125 gal marine tank with 2 lionfish, a snowflake eel, and one Sciades seemanni Columbian Cat.
<Mmm, this last is a social animal. Much happier w/ some of its own kind>
I almost bought a trigger until I read that the triggers hate the cats clicking noises. I am contemplating selling all bought <but?> the cat and converting to a brackish environment. I read that the cats do better in groups.
<Many species do>
My current cat is 7 to 8 inches. I want to get 1 or 2 more but cannot find them large enough. If I buy a 2 or 3 inch cat, will the larger one be aggressive toward it?
<Not likely, no>
My second question is about acclimation. I wish to add Mono argenteus and Sebae but these are almost always sold in freshwater. I was told that you can almost take them directly from fresh and put them into a marine environment. Is this true?
<Yes>
Can I do the same with archers and the cat?
<To a lesser extent, weeks instead of days, yes>
Or am I safer to set up another tank to slowly convert them to marine or brackish? Thanks for the help!
<This last is a much safer, better approach. Bob Fenner>
Re: Sciades seemanni and Mono Questions, more re acclim. to SW, impt. notes re Toxotids, ID and sys.
Hi Bob,
<Neale>
I just saw your reply to one brackish one about monos and catfish.
<Yes... responded as it was over a "day" back/old>
Would just add this: You are quite right that (subadult to adult) Sciades catfish and (any age) Monodactylus can be converted to marine conditions quickly. I'd use the drip method across an hour, as if they were swimming through an estuary, but yes, you could in theory dump them straight in.
<Ahh, please do send your input to the querior as well>
But Archers are a whole other kettle of fish. There are three species in the trade, each equally widely sold, and one of them is a freshwater to low-end brackish species, Toxotes microlepis.
<Rare in the U.S.>
It will die kept in marine conditions for any length of time. Frankly, it's unhappy above about SG 1.005. The other two species, T. chatareus and T. jaculatrix, will tolerate marine conditions though they're best kept around SG 1.010.
<Definitely send this along as well>
Diagnosing the three Archer species is tricky, but there are some drawings that should help on my web site, here:
http://homepage.mac.com/nmonks/Projects/FAQ/3c.html
Cheers, Neale
<Thank you. BobF>
Sciades seemanni and Mono Questions
<<By way of a follow-up to Bob's reply. I would just add this: Bob is quite right that (subadult to adult) Sciades catfish and (any age) Monodactylus can be converted to marine conditions quickly. I'd use the drip method across an hour, as if they were swimming through an estuary, but yes, you could in theory dump them straight in. But Archers are a whole other kettle of fish. There are three species in the trade, each equally widely sold, and one of them is a freshwater to low-end brackish species, Toxotes microlepis. It will die kept in marine conditions for any length of time.
Frankly, it's unhappy above about SG 1.005. The other two species, T. chatareus and T. jaculatrix, will tolerate marine conditions though they're best kept around SG 1.010. Diagnosing the three Archer species is tricky,
but there are some drawings that should help on my web site, here:
http://homepage.mac.com/nmonks/Projects/FAQ/3c.html
Bob believes that Toxotes microlepis rare in the US market, but German author Frank Schaefer argues it is the most widely traded. My own experience is that all three species occur roughly as often as each other,
and I've seen specimens of all three species on both sides of the Atlantic.
So do check which Archerfish you have before acclimating them to saltwater conditions. Cheers, Neale>>
Re: Sciades seemanni and Mono Questions, hlth, env. of cats    3/17/10

I read the article about the Seemanni in the magazine. It was very informative.
<Good to hear.>
I do have one other question for you. I did a major cleaning in my tank before adding the smaller cats. The large Sciades Seemanni had a cloudy eye for a day and then it cleared up.
<Curious.>
The cleaning stirred up the tank and was fairly intense so it probably stressed the cat.
<Perhaps. These are estuarine fish, so in theory, they're pretty good at adapting to sudden changes. But that said, if the tank is rather small, and you're moving your hands about the tank a lot, then they could feel pursued.>
I do not know if it was the cleaning or the addition of 2 small cats but the large cat rarely eats.
<Likely stress rather than company.>
He used to eat anything and everything, now I can barely get him to take silversides and krill. He has eaten a couple of krill in the past 2 weeks and only a few mixed pellets. The small ones are eating fine. The large one does not seem stressed but I can put a large silverside in front of him and he wants nothing to do with it. He used to go crazy for them. Any ideas as to what is going on?
<Remind me again what the salinity is. Almost always, when brackish water fish go off their food, it's because they're not happy with the environment they find themselves in. At minimum, check the pH and the specific gravity.
For a subadult Colombian Shark, you should be well above SG 1.005, and realistically around 1.010. The pH should be firmly in the basic range, 7.5 to 8.2 being ideal.>
He is eating enough to survive...maybe, but maybe only a 5th or 10th of what he used to. Thanks guys. I only recently found wetwebmedia.com and am loving it. It is a great resource.
<Happy we can help. Cheers, Neale.>  

Surfacing Columbian sharks and feeding 11/29/09
Hey Bob, SmallIslander here,
<Hello,>
I am over in the Turks & Caicos Islands and while we have the best beaches, we don't have a pet shop. I am new to aquariums and have started off with a 55 gallon (will get a bigger one eventually) with 3 Columbian Sharks and a host of a lot of other fish that I believe are all brackish water fish.
<Sounds fun.>
I have a fresh water tank and the exporter who sold and sent me the fish said to add salt. I added about 23 teaspoons. (they seem to be doing better, should I add more? How much more? Is that enough?
<A "teaspoon" is a pretty meaningless amount. One level teaspoon is approximately 6 grammes (this is easiest in metric, so you'll have to go along with me on this). Full strength seawater is 35 grammes per litre, or slightly under 6 teaspoons of marine salt mix per litre. Colombian sharks are happiest in middle to full strength seawater, so something around three teaspoons per litre of water is what you need. If you visit my web site, there's a little program called Brack Calc that can be used to convert between metric and gallons, should you prefer to work that way.
http://homepage.mac.com/nmonks/Programs/brackcalc.html
So, your tank is 210 litres in size, and you're adding 23 teaspoons. That's 0.11 teaspoons per litre, less than one-three hundredth of the amount of salt in seawater. A trivial, indeed useless, amount. You could drink water with that salinity and come to no harm.>
Can you tell me why my Columbian sharks keep surfacing in front the water filter, is it that they like the current?
<This is "normal" behaviour under the circumstances. It is the nature of Columbian sharks to migrate up and down rivers. In aquaria, they tend to swim close to the filter, presumably because the water current is strongest there.>
I am not sure about the water as I should have a test kit by Wednesday. But I treated it for a few days before the fish cam with tap water treatment and Nitraban balancer. Another problem is that I thought the sharks would eat the tropical flakes. .. not at all.
<They will eat catfish pellets, but they do need a mixture of wet-frozen foods as a staple. Chunks of white fish fillet, prawns, mussels, squid and so on all work well. Some mullet species contain Thiaminase, so you have to be careful here. Do read this article before planning the diet:
http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm
A mix of wet-frozen seafood plus some good quality catfish pellets should balance things out without too much bother.>
I have tried shrimps from the grocery store and frozen mullets. NO luck yet. I had them from Friday and they haven't eaten. Everybody else did. My last problem is one of the sharks seem to have a busted eye (its white as if he hit it on the aquarium or decoration inside. I don't think he can see out of this.
<A common reaction to clumsy handling. Damaged skin on the outside can improve on its own assuming the eye itself isn't damaged.>
Also I noticed his belly has shades of black light dots, can this be his normal skin?
<Yes.>
What do I do? Another shark has a bloated belly but all are swimming healthy. Should I add Epsom salts?
<No. You need to be adding a lot more marine salt mix. This will take care of general hardness, carbonate hardness, and salinity all at the same time. I'd start at 9 grammes/litre (SG 1.005 at 25 C) for now, to give your filter some time to adapt to brackish conditions. After that, you can nudge the salinity up across a few months to wherever you want to maintain it. Do read some of the brackish water articles here at WWM or on my web site; you may also find either my book or Frank Schaefer's Aqualog book on the topic worthwhile.>
If so how much. When to I add the algae control?
<Don't.>
Thanks. This is the best site online.
<We like to think so.>
SmallIslander
<Cheers, Neale.>

Re: Service company and feeding 7/8/08 I was able to download one of the shows by Reece. Listened to the first half before I made some dinner for the kids. Pretty good, I'll be keeping an eye out for your appearance. I'm sure it'll be interesting! Bout the same the same story with the B/F currently, I'll keep working on it. I left them by themselves with the feeder this three day weekend and this morning they all looked fantastic, so that's refreshing. (Amm-0, Nitrite-0, Nitrate-.15, Phosphate-0) You know, the service biz ain't no joke, it's been very nerve-wrecking for me so far. <With great rewards...> Normally you're with your tank every minute that you're home, observing. Can't do that here, it's tough. I'm sure you know exactly what I'm talking about, it's hard to describe. Gonna keep on keeping on though, I'm thriving off of it. The other tank is a 220G display with 80G sump, I built it in-wall in the guys basement. This was a SERIOUSLY underestimated project! The entire time I was very overwhelmed. <Live... and hopefully learn...> Has all the bells and whistles, halides, MR2, GEO 624, CL with 4-way OM) Took me two months solid (which would now take me half as long now that I've done it, and the owner knew this going into it) Any advice? <Ask for more money, or chalk all up to experience and move on> I just read over the "Silver-Tipped/Columbian/Jordan/Ariid Cats" and I like what I've read. You didn't mention fish but at least one of mine would be this Catfish. My pops always had em growing up, LOVE the look and the way they glide through the aquarium, definitely shark-like. I'm interested in adding a small shoal, (3) to a 110 FOWLR I currently have here at the house. Upon further research it seems I may have put together a nice environment for this species. My question is, at what age will they be completely comfortable to full strength sea water? <With growth, more than time, when they're six to eight inches in length... about a year possibly> As long as I can remember, they've always been offered at the 3"-4" range, usually on the lower end of that. Will youngsters be ready for a FOWLR assuming I went through the recommended acclimation procedures? <Yes> I'm thinking three of them with an adult Volitans would make a great aggressive display. <Okay> Pretty cool Walt Smith is a friend, along with many others, Calfo, Michael, Paletta, come to mind among others. Wow. My friends just go to bars and clubs.... lol. <Mmmm, this is about all we do as well... while talking about aquariums of course> Nice talkin to ya. <BobF>

Columbian Cat Shark, comp., sys.   6/3/08 I have bought three Columbian Cat Sharks from my LFS. They were about 3 inches (2 weeks ago). I have put them in my 65 gal Reef Aquarium. Tanks mates are 2 common clowns and a six lined Wrasse which I think are going to be on the menu in a few months, but I have another marine aquarium they can be moved to. <Interesting set up. The Shedd Aquarium in Chicago used to keep some species of Sea Catfish (I think Ariopsis felis) in a tank that was essentially a giant reef tank in the Rotunda. Sea Catfish look *a lot* like small sharks, and it was quite something to watch them cruise that tank.> So far they seem fine with the soft corals and clean up crew, but when they get larger which is apparently going to be sooner rather than later given their current growth rate are they likely to eat the clean up crew as well, hermit crabs, turbo snails, emerald crab and common urchin? <More than just "likely", it's probable! These catfish are completely opportunistic predators, and a significant amount of their diet consists of crustaceans of various times.> The tank is furnished with macro algae, live rock, bubble tip anemone, devil finger coral, mushrooms, xenia and yellow star polyps (sorry about spelling?) These fish will be the priority in the tank and I wanted to create a aquarium matching there natural habitat so what should I used to create the biotype? <Sea Catfish are estuary/inshore water animals. You find them in harbours, around rocky reefs (oysters beds for example), mangroves, sandy estuaries, and so on. So while they're not really picky animals, they have a preference for shallow water habitats where they stick close to the substrate. Their whiskers, electric sense, and (apparently) echolocation sense all help them to find food in turbid waters where other predatory fish would be at a disadvantage. In other words: classic catfish habitat! A perfect tank for them would have some big rocks (with sessile invertebrates if you wanted) and caves, an open sandy area, and a HECK of a strong water current. Not too much light if possible; or at least concentrate the light on the parts of the tank where the corals are, and leave some part of the tank shady. That said, they're wonderfully adaptable fish, and provided they have swimming space and a few friends of their own species, they aren't demanding. They mix well with most marine fish, though I've found they don't get along with Triggerfish -- triggers use clicking sounds as threats, so misunderstand the clicking noises Sea Catfish employ when communicating. The triggers attack the cats, the cats start clicking because they're frightened, and the trigger gets even more irate. As you can imagine, this isn't what you want, because both species are well armed and able to dish out serious damage. Triggers have whopping great bite, while Sea Catfish have an anti-coagulant bite (causes serious bleeding) plus venomous spines.> Thanks <You're welcome, Neale.>
Re: Columbian Cat Shark
  - 6/3/08 Thanks Neale, They look completely stunning in a Reef Aquarium, no one believes me when I tell then they are not actually real sharks and will not grow 6ft. The way they move and cruse the aquarium mid level and explore the caves makes them look remarkably like Reef Sharks. <Have seen them thus, and yes, the likeness is amazingly close, right down to the way they swim. One ichthyology text book I have begins the chapter on catfish by saying simply "Catfish do everything". Bold stuff from a scientist, but really very true. An amazing group of fish, and the more species you keep, the more impressed you become with their adaptability.> Theirs colours have changed from washed out silver to dark metallic steel grey, with a brownish dorsal fin, the rest of the fins are black with white tips. They have great appetites and are growing by the day. <Juveniles grow very rapidly. They level off around about 15-20 cm, and only very infrequently do aquarium specimens reach their maximum size in the wild of 35 cm. Some experienced aquarists have opined that there may be more than one species in the trade offered under the Colombian Shark Catfish moniker, and hence the variability in maximum size.> I have a very strong current in the tank from 4 power heads and they love the current. Not seen them sit on the tank bottom once... but then they even sleep on the wing...whoops...fin! Never stop! <Indeed so! They are migratory in the wild, moving up and down estuaries all the time.> Feeding them enough to maintain there activity level will be the challenge in a Reef tank without upsetting the water quality ! <Adults do need rather less food per unit body mass than the juveniles; it's generally recommended that big catfish be fed only every other day. I tend to prefer to simply offer small daily meals, ideally things that are high in fibre (like unshelled crustaceans) so that the fish feel full without too much protein (i.e., nitrogen) getting into the system.> Thanks again. <Cheers, Neale.>

Columbian Cat Shark summer heat et al.  5/13/07 I have 3 4 inch CCSs in a 55 gallon tank (more on that later) and am worrying about the water temperature in my summertime, non-air-conditioned apartment.  Because my apartment is getting warm, the tank is at 80f (have a heater, normally set at 77f, currently removed; it's not even high summer yet).  Basically, should I be looking at buying a chiller for the tank before it gets any warmer?  Any ideas on cheap/diy chilling? <All sorts... posted on WWM... however, I would first try simply leaving your aquarium lights turned off during the day, perhaps less cover over the tank, adding a fan to speed up evaporative cooling...> As for the tank (currently brackish 1.010) how big should the sharks be before they're fully marine? <Mmm... six to eight inches overall likely>   Current plan is to build a new, large reef tank and put 'em in there, and it seems reasonable to get that going as soon as the sharks are happy with it.  Our freshwater fish live in shame in an old Tupperware bin, I promised them the 55 gallon back once the sharkies get a new home. <Heeee! I like to keep my promises> Thanks! Paul <Welcome. BobF>

Do Columbian sharks need light  12/20/06 <I apologize for the delay, Shereeann. We are having problems receiving certain formats of email, rendering some emails unviewable. I have not been available to resend these to the crew for response purposes, and I apologize. Original message as follows. -JustinN> <Again, thank you my friend. Bob> Hello.  First let me tell you guys that your site is the best.  The website has helped me many times.  I own two Columbian sharks (4 inches) and have been trying to do everything properly to raise them to their full potential, except one thing.  I never replaced the broken aquarium light for the tank.  Basically, they live with no light.   <Mmm, actually only needed for your appreciation of these beautiful animals> I try to open the bedroom window for them in the daytime but where I live there are many trees and they never really get any good sunlight. <As is the case in the wild, assuredly> At night they live in total darkness and sometimes a few hours of bedroom light.  I always thought that these kind of fish like the dark but I could be wrong.  Please tell me what kind of light they need to grow.  Is bedroom light enough? <Yes> Do they have to have direct sun rays coming at them? <Mmm, no... no for instance, nutritional needs like Vitamin D synthesis...> Can they live in total darkness 24/7? <Mmm, is not totally dark is it?> By the way, they live alone just the two of them.  Thank you for your time in advance. Shereeann <Thank you for writing, sharing. Bob Fenner>

Columbian Sharks  12/19/06      <Hi, Pufferpunk here> Hey I have a couple questions.  One is that my friend just gave me two catfish because they got too big for his tank.  He said they were  Columbian catfish.  Right away I was worried that they might be too big to start acclimating to brackish water since they are suppose to be brackish when small and full marine when full grown.  Is it too late for me to acclimate them to the right water conditions?  <It is never too late to bring a BW fish from FW to BW.  Just raise the specific gravity .002 weekly (with marine salt), to the desired SG (probably around 1.015-1.018, for now).  Are there other BW fish in this tank?  Is the tank cycled?>   One is  about 8in. and the other about 6 1/2in.  Another question is, both have a black spot on their sides by their gills is this normal?  Please help me make these beautiful cat fish happy. <Your new fish sound fine.  They are schooling fish though.  They will grow close to 18" & will need quite a large tank, since they are active swimmers.  They will eat anything they can fit into their large mouth.  ~PP>

Columbian Sharks  10/26/06 Hello WWM crew, I have a 55G (standard florescent 36 watt, Fluval 205, protein skimmer, 200GPH powerhead) with 50 lbs LR, 3 inch sandbed, 2 blue damsels, 1 Pseudochromis, 1 scooter blenny, 2 urchins, 1 Condy, 10+ blue legged hermits, 1 turbo snail, 1 chocolate chip star and 2 (2 inch) Columbian sharks. <These will outgrow this system>   I am currently completing the cycling of a 75G (T5 florescent 64 watt 6500k, Emperor 400 BIO-Wheel, aragonite substrate) for the Columbian sharks. <Oh, good> Here's the problem... I am accepting an emergency adoption of 4 Columbian sharks (8 inch, 6 inch, and [2] 4 inch). <... will need more room...> The new shark will be in the 75G while the 2 Columbian sharks I currently own will temporarily remain in the 55G.  I am picking up a used 150G (and budgeting/shopping for larger) to quickly began cycling for the growing Columbian sharks. <Oh! Even better> I currently feed the Columbian sharks a diet of dried blood worms, frozen krill, frozen brine, and flake (that they steal from the damsels). Questions: 1.  It seems as though 300+ gallon tanks are getting slightly out of the standard consumer market.  Do you recommend any particular websites/brands to look at in this size? <Mmm... do a look/see re acrylic fabricators in your area... unless price isn't really a large factor... And the possibility of DIY...> 2.  Would a size-adjusted duplication (for 150 or larger when purchased) of my 75G setup be the best for these Columbian sharks? <Would/could work out fine> 3. Is there anything you would recommend to go with the Columbian sharks (i.e.-not fish but... anemone, cleaners, etc.)? <All sorts of suitable animals... fishes and non-fishes...> 4.  Although I have tried to do my best with research, any recommendations on current setup/procedures would be welcome. Sorry for so many questions, but it appears WWM is the best source for us "one-day-wanna-be" experts out here. Thanks, Steve <Mmm... and you have perused the bits on these Ariid Cats: http://wetwebmedia.com/ariidcats.htm and the linked files above? Bob Fenner>

Tank size question regarding Colombian Cat Shark (Arius seemanni)  - 10/13/06 Hello, <<Greetings, Glenn. Tom>> I am thinking of buying 3 and keeping them (alone) in a 110-gallon tank. I have not the opportunity to buy a bigger tank later on because my room is not big enough. So my question is: "Will this size tank eventually become to small for them, or will it be tolerant for them as adults'. <<I see no reason why a 110-gallon tank won't accommodate three of these fish. Since you're asking this question, you've done some research and know that these animals are brackish water species. They can even require full marine conditions in adulthood. Provided that you're prepared to 'transition' them as they mature, I wish you luck with your venture and enjoy.>> Glenn <<Tom>>

Re: Tank size question regarding Colombian Cat Shark (Arius seemanni) <<Hello again, Glenn.>> Sounds good... now, what would you recommend, still talking about my 110 gallon tank and the three Arius S.: only having two instead - giving them more space but the lack of the third - or still going for the three - giving them a better feeling being in a school, but less space. <<Glenn, strictly speaking, I'd love to see these big fish have all the room you can give them, which would mean going with two versus three. A consideration here is the possibility that something unforeseen could happen to one of your fish down the road. If its tank mate is too large to safely introduce a new "buddy", you're down to one pet. That's a decision you'll have to make but I do want to throw it out for what it's worth. Tom>>

Columbian sharks... in gen.  6/5/06 <Hi, Pufferpunk here> So we have read the many postings that you have about protozoa infections but we are not understanding some of it or we are not doing something right. We have 4 (previously 5) Columbian sharks in a 75 gal. tank. <Since they can grow up to 18" each, you may need to upgrade to a much larger tank.> 2 are about 5 in. and 2 are 4in. With them we have 10 guppies that we bread and raised, <Will eventually be eaten by the sharks> a Pleco and 1 (previously 2) Chinese algae eaters. We noticed what looked like a spider web on 1 shark and 2 days later he died and was covered in white web looking stuff. Went to pet store and found a picture of protozoan symptoms-put AP-Plus Cure -Ick in as directed-3 days later they started eating again and seemed all better. Then about 1 wk later they stopped eating again and got lethargic and were digging their noses in the rocks again-1 of the Chinese algae eaters died and 2 guppies. We started putting the medicine in again 3 days ago but they are not responding this time-1 shark even has slime on him that just showed up today AFTER 3 days of treatment. Please help - what do we do??? Do we need to super clean out the whole tank and replace the gravel? We fear that will over stress them and they may die from that??? The little fish seem to be OK except for the 2 that died 2 days ago. Our pet stores don't have any other meds.    <Columbian sharks are brackish water fish that require marine conditions as adults.  I'm afraid as long as you are keeping them in freshwater, their immune systems will be compromised, causing disease & short lifespans.  I suggest putting them into the proper conditions for healthier, long lived fish.  substrate should be crushed coral or aragonite, to keep the pH around a steady 8.  Your FW fish will not appreciate BW conditions, especially the Pleco.  ~PP>

Columbian Shark  Question  - 4/11/2006 Hi there! <Greetings> I have spent hours and hours (well. if I put all the hours together, they would probably add up to months!!) reading your fantastic site. And in preparation for my new marine project, I am currently reading your (Robert Fenner's) amazing book "The Conscientious Marine Aquarist". It's a fascinating book that has taught me a huge amount already and keeps me up reading into the late hours of the night :-) I highly recommend it.   <Me too> I was wondering if I could ask a question regarding my current situation. First, I will explain how I got there!! <Okay> I decided to add another tank to my collection - this time a brackish one since I love the Figure Eight Puffer. Once my 20 gallon was cycled and brackish-ized (!), <Heee! New term> I went to the local aquarium shop to purchase my Figure Eight Puffer. They recommended that I add to the tank two Columbian Sharks (Hexanematichthys seemanni) I was surprised as I thought Figure Eights needed 20 gallons each, <They do... and these catfishes much more> but they convinced me that the sharks would be a wonderful addition. And so off I went with my three new brackish friends . well, friends to me, not to each other. Needless to say my research was correct - I soon had to remove the two poor sharks when I woke up one morning to find they had both lost most of their fins - but I am relieved to say that after being placed in another tank and with much loving care and anguish on my part the fins are finally growing back. <Are very tough animals in good settings> Now, before I went to the store I hadn't heard of Columbian Sharks and just trusted the store's claim to "expertise" at the time. Since then, I have researched them and realize that as adults they need marine water and a much larger tank. <Yes> Since I am moving in a couple of months, I will be buying them a new tank when I move to my new place. So, now to my questions! 1. I know that the sharks need to be gradually acclimatized to a marine setup when they are adults - but how can I tell when they are adults? Is it according to size, months, years? <Size of the fish mostly... more salty with growth...> 2. And how gradually should they be acclimatized once they reach the age when their s.g. should be increased? <A thousandth or two per week of spg change is about right> 3. I wish my sharks to live a long, happy and healthy life and therefore before I invest in their new tank, I wonder if you could advise me on size. I was thinking of getting a 72" long tank. Is that a good size for them? <Yes> 4. Keeping in mind the sharks' adult size, health, happiness and bio-load, would it be possible to add any other marine fish to the new tank? <Yes> Or should they be kept on their own? <Are fine mixed with other compatible livestock... and nice to have motion, life in the middle and upper reaches of the tank> My favourite other fish are the Porcupine Puffer or a Trigger Fish. However, I know that both of those are aggressive species. But since the sharks will grow quite large, I was wondering if this will keep the Porcupine or Trigger away from the sharks and thus make them compatible. But if not, then I will not take the risk. <Easier going, starting small specimens, species of these would likely go fine> Many thanks for all your hard work in answering everyone's questions. You provide us with a very much needed support system and with an unending supply of knowledge. <Thank you for sharing, your upbeat note. Bob Fenner> Best wishes to you all, Sandra P.S. My Figure Eight seems very happy on his own. He has even trained me to understand what he wishes to eat. When he swims to the front of the tank and catches my eye, he will then look up when he wants shrimp but will hold eye contact with me while swimming downwards when he wants a snail. I learnt this the hard way - when he started doing this and I gave him the wrong food, he refused to eat but now that I understand his "language" I get it right every time and he eats his dinner to the very last bite!!

Lonely Schooling Columbian Shark  7/28/06 Hey Guys, <Hi Joe, Pufferpunk here> I think your web site is great and I have learned a lot from you guys. <Glad to hear it!> Anyway I have a Arius seemanni he is about 6.5in and mostly just swims around the top of my tank. The other day he jumped out I was luckily there and put him back into the tank, he immediately started swimming like nothing happened. <I hope you add a nice, sturdy cover to that tank after that!> I did notice that his eyes where kind of foggy and he seemed to bump into stuff more often.  But as of today 6/28 his eyes look good and I was told he had an infection.  What do you think? <Whatever it was, seems to be gone now.> Also he is in full saltwater and all the water parameters are perfect.  He has no other catfish friends and I was wondering if he would be happy and school with coral catfish? If so how many should I get? <Since this is a schooling species, he would definitely like some friends like himself.  The fact that they can reach sizes of around 18" though, means a HUGE tank in their future, for a school of 5-6.  ~PP> Thank you for your and knowledge, Joe

Columbian Catfish & Brackish Water  6/25/06 Hello! <Hi Lou, Pufferpunk here> I have a few questions for you!  First--a little  history.  We set up a 10 gallon community tank for our 7 year old last  fall.  All was well--he does a great job testing the water and caring for  his fish.   <Good for him, at 7!  I bet he had a little help...> Anyway, Christmas Eve, my sister-in-law bought him two silver-tipped sharks and an algae eater. (Even after I told her that his  tank was at capacity and a PEACEFUL tank.)   <Bad, bad, bad idea to ever give pets as gifts!  I hope she was well scolded!> She gave them to him at 9 pm  Christmas Eve, so we had no choice but to put them in the 10 gallon tank.  They did very well but got fairly large.   <No surprise there--they can get to 18" if housed properly.> All three are at least 6 inches  long.   <Ummm... do you have 2 or 3?> We started to have water trouble and one of our zebra danios mysteriously, completely disappeared.   <Gulp!  Large water changes are in order for these fish, with voracious appetites & lots of waste in return.> We moved the sharks and algae eater into a 55 gallon 3 weeks ago.  (We do keep the water brackish for  them).   <The other fish you have will not appreciate any salt.  As far as "brackish" what do you mean?  Even for very low-end BW (a specific gravity of 1.005), it would require roughly around a cup of marine salt/5gallons.  At the size your Columbian sharks are now, they should be around mid-range BW, 1.010 (you'll need a hydrometer to measure SG).  They will require marine conditions as adults (at least 1.020).  They are also schooling fish.  So for a school of 18" fish, you're going to need a really HUGE tank!  (Time to go back to the sis-in-law for more scolding!)> My first questions are about the sharks.  They have always swam together.  Now that they're in the bigger tank, we can see them  better.  They swim almost vertical and push their whiskers out of the water near the filter.  Is this normal?   <Is there enough current or air-flow in there?  Check the water parameters (ammonia, nitrIte, nitrAte, pH)> They are very skittish and when startled, shoot back and forth across the tank at lightening speed.   <They might need more decor to feel safe.  Even some floating plastic plants might help (live plants don't do well in BW)> They  appear healthy and are growing like crazy but seeing their bellies constantly seems strange.  I thought they were bottom feeders?   <Generally anything with whiskers are.> Today they are actually swimming separate more, which is shocking and not constantly at the  top but still going up the sides.  Also, could they mate?  What would  we look for?  (Just baby sharks?) <Possibly but not in those conditions & tank size.  They will probably stunt in there.> We also have 3 tiger barbs and a gourami in the 55 gallon tank. <Opps!  Not BW fish.> The  barbs seem to nip each other and chase around in circles a lot.  Is this  normal?  Are they being "playful" or trying to harm each other?  It  seems like the same two going at it while the third darts in and out between  them. <Typical barb behaviour.> In a couple weeks, we were going to add another gourami.   <Not a BW fish.> Any other  suggestions?  We'd like a colorful tank but don't want to load up on any  more fish that will get so big!  What about a Bala? <Balas grow huge and again are not BW fish.  I think you should stick with these 2 (or 3?) & start saving for a larger tank & bags of salt.  They are fast-moving, active fish that may be disturbing to peaceful fish.  Do more research on BW fish.  ~PP> Thank you very much for your help!! Lou

Columbian Catfish & Brackish Water  6/25/06 Hello! <Hi Lou, Pufferpunk here> I have a few questions for you!  First--a little  history.  We set up a 10 gallon community tank for our 7 year old last  fall.  All was well--he does a great job testing the water and caring for  his fish.   <Good for him, at 7!  I bet he had a little help...> Anyway, Christmas Eve, my sister-in-law bought him two silver-tipped sharks and an algae eater. (Even after I told her that his  tank was at capacity and a PEACEFUL tank.)   <Bad, bad, bad idea to ever give pets as gifts!  I hope she was well scolded!> She gave them to him at 9 pm  Christmas Eve, so we had no choice but to put them in the 10 gallon tank.  They did very well but got fairly large.   <No surprise there--they can get to 18" if housed properly.> All three are at least 6 inches  long.   <Ummm... do you have 2 or 3?> We started to have water trouble and one of our zebra danios mysteriously, completely disappeared.   <Gulp!  Large water changes are in order for these fish, with voracious appetites & lots of waste in return.> We moved the sharks and algae eater into a 55 gallon 3 weeks ago.  (We do keep the water brackish for  them).   <The other fish you have will not appreciate any salt.  As far as "brackish" what do you mean?  Even for very low-end BW (a specific gravity of 1.005), it would require roughly around a cup of marine salt/5gallons.  At the size your Columbian sharks are now, they should be around mid-range BW, 1.010 (you'll need a hydrometer to measure SG).  They will require marine conditions as adults (at least 1.020).  They are also schooling fish.  So for a school of 18" fish, you're going to need a really HUGE tank!  (Time to go back to the sis-in-law for more scolding!)> My first questions are about the sharks.  They have always swam together.  Now that they're in the bigger tank, we can see them  better.  They swim almost vertical and push their whiskers out of the water near the filter.  Is this normal?   <Is there enough current or air-flow in there?  Check the water parameters (ammonia, nitrIte, nitrAte, pH)> They are very skittish and when startled, shoot back and forth across the tank at lightening speed.   <They might need more decor to feel safe.  Even some floating plastic plants might help (live plants don't do well in BW)> They  appear healthy and are growing like crazy but seeing their bellies constantly seems strange.  I thought they were bottom feeders?   <Generally anything with whiskers are.> Today they are actually swimming separate more, which is shocking and not constantly at the  top but still going up the sides.  Also, could they mate?  What would  we look for?  (Just baby sharks?) <Possibly but not in those conditions & tank size.  They will probably stunt in there.> We also have 3 tiger barbs and a gourami in the 55 gallon tank. <Opps!  Not BW fish.> The  barbs seem to nip each other and chase around in circles a lot.  Is this  normal?  Are they being "playful" or trying to harm each other?  It  seems like the same two going at it while the third darts in and out between  them. <Typical barb behaviour.> In a couple weeks, we were going to add another gourami.   <Not a BW fish.> Any other  suggestions?  We'd like a colorful tank but don't want to load up on any  more fish that will get so big!  What about a Bala? <Balas grow huge and again are not BW fish.  I think you should stick with these 2 (or 3?) & start saving for a larger tank & bags of salt.  They are fast-moving, active fish that may be disturbing to peaceful fish.  Do more research on BW fish.  ~PP> Thank you very much for your help!! Lou

FW Columbian shark size question / livebearer follow-up   6/17/06 Hi again Jorie <Hi there> In the previous email you sent on how the Colombian gets big. Yes I knew about that but it would take a while before they get big. <True, but I guess I never understood buying such a specimen if you don't have the setup ready, as good intentions can often be thwarted by financial issues, etc.> What size of tank would you recommend for the adult Colombian sharks? <Some recommend starting with a min. tank size of 75 gal., while others say start with a 120+ gal. tank.  Also, beware that when this fish grows, it may eat smaller fish it can get into its mouth...> Yes, I am planning on raising the fry but after wards I am going to give them away to friends that have aquariums and that want some or even sell then to pet shops <Do be sure to check before had that the fish stores you want to sell your fry to will accept them - I've had situations where stores refuse even donations, because of the sheer quantity they've already got on hand...> <Jorie>

Arius... Wal-Mart, Mis-served consumers  - 05/29/06 hello my name is kylie and I have recently purchased 3 black finned sharks and I cant seem to find any information on them and am only 15 so I have no idea what to feed them or how big they get I bought them from Wal-mart and they said that they only get to be about 6" but am not sure and I would like to know if feeding them stuff like frozen brine shrimp would be a good idea or not? <... Please read here: http://wetwebmedia.com/ariidcats.htm and the linked files above> because I was researching some stuff about a Bala shark because that what I thought they were the same thing and found to be incorrect and I was wondering if a 10 gallon tank would be big enough along with having 4 guppies in the tank with them? <No... this venomous catfish gets too big, is brackish to marine...> I would appreciated very much if you could help me out with this because I do not wish for them to die so if you could plz reply ASAP it would help greatly and is it ok to feed them regular fish flakes or is there something specific I need to feed them?   Thank you for your help,   Kylie <Do research ahead of purchasing livestock. Bob Fenner>

Another <Arius> question  - 05/29/06 I have another question about my black finned sharks is it strange that they swim in a circle in one corner of the tank? <Mmm, no and yes> am asking because they do this all day and am worried that there might be something wrong with them <There in a freshwater system... and they're not freshwater animals...> and I just tried to feed them and its like they didn't even notice the food was there so is there something wrong with them or is this usual? Thank you,   Kylie <Read my young friend, now. I would return these animals to Wal-Mart. Bob Fenner>

Ich and Black fin sharks  - 5/17/2006 Hi, <<Hi, Jennifer. Tom here.>> I have a problem that I can't seem to resolve and I'm not sure if it too late for my fish.  I have a 10g tank with 2 black fin sharks (about 2-3 inches), 2 platies, and 1 Pleco. I had 3 BF sharks, but one died (stress I think..) Also, had 3 platies but 1 died. (I think from being attacked by the other fish because one day 1 of it's side fins was half gone and it's tail fin was pretty beat up looking.  Anyhow, I noticed some bubble looking spots on the 2 BF sharks and went out and purchased an Ich treatment.  The guy at the fish store said they use it all the time and it works fast.  So I followed the 3 day process, and they seemed to look a little better.  I skipped one day as directed and am repeating the process.  This is day three and they look way worse than before.  I also haven't seen them eating and one looks as though it's mouth is fuzzy.   <<Hazarding an educated guess, Jennifer, the white spots you first noticed were the beginning stages of Columnaris. I wouldn't discount Ich, of course, but the "fuzzy" growth around the fish's mouth is Columnaris. I'd recommend you begin treating with Melafix immediately. Once this bacteria affects the organs of the fish, antibiotic treatment is in order and you're not set up for that.>> None of the other fish are affected by the Ich, just the sharks.  Could this be something else?  Are my sharks pretty much goners and if so should I put them out of their misery?  I have no idea what to do. <<Treat with Melafix and, if this takes care of the problem, find a new home for your sharks. In the proper environment and correct conditions, these fish grow to be VERY large. They're also not "true" FW fish but, rather, will require marine conditions as adults. Your Pleco is going to need a larger tank than what you have now, as well. Depending on the variety of Pleco you have, these, too, can grow quite large. Much to learn before any more purchases, Jennifer. This site is the best place to start.>> Jennifer <<Tom>>
Re: Ich and Black fin sharks
 5/18/06 <<Tom>> Thanks, I'll try the Melafix.  Yesterday I did a water change again and they seem to be back to eating like they were before (chasing off the Platies and skimming the water surface aggressively for food).  Hopefully this is a good sign. <<Yes, it is, for now. This will change as the fish mature, though, as they will tend to stay toward the bottom of the tank.>> <Umm... this "good time" will not last... this catfish is a brackish to marine species... will die soon unless moved to more suitable conditions. Please read here: http://wetwebmedia.com/ariidcats.htm and the linked files above> I know the Sharks are going to get rather large as well as the Pleco and will purchase a much larger tank in the future.  They are living in a brackish tank right now, I'll have to look into marine tanks and read up on the care of those.   <Oh! Sorry re... thought these were in freshwater... Loricariids/Plecos don't like/tolerate much salt... Bob Fenner> <<Sorry that you seem to be getting "double-teamed", Jennifer. Both Bob and I assumed your fish were in FW and, of course, he's right about the Pleco not tolerating "salty" conditions for long. (I apologize for the apparent conflict in information.) By way of explanation, we receive a number of questions regarding this fish - the Shark, specifically - and, admittedly, it remains to be one of my "pet peeves" among those who sell/distribute these to "unknowing" consumers. In the end, however, it is we, the aquarists, who need to research and be informed prior to purchasing. It sounds like you're aware already of what will need to be done, which is great. Hope this hasn't proved too confusing for you and we look forward to hearing from you in the future. Tom>>

Black fin shark's size ... Arius    5/4/06 Hi, <<Hello, Jennifer. Tom with you this afternoon.>> I have 3 black fin sharks who are about 2-3 inches long right now. <<I'm going under the assumption here that these are Hexanematichthys seemanni (aka Columbian Shark Catfish, White-tip Shark, et. al.).>> I have searched the internet and found several sites that say they grow to be about 14 inches long. <<This is probably the norm in aquaria if properly cared for under the correct conditions. There are reports of these animals growing to two feet in length but this wouldn't be expected, generally.>> When I went back to the store and looked at the description card provided it states they only grow to be up to 6 inches. They also said Iridescent Sharks grow to be up to 12 inches.  Are they correct or are they misinformed? <<Let me put it this way, Jennifer. You had the good sense to research your fish and found that they can grow to over twice the size that this "store" describes, which is actually better than their depiction of the Iridescents that can grow to 36-40 inches and shouldn't be sold to "hobbyists" in the first place. They're not "misinformed", they're deliberately "misrepresenting". ;) Now, back to you, which is what I'm really here for. Your fish, as you may have discovered, must make a transition from freshwater to brackish and, ultimately, to marine conditions at maturity to survive and thrive. They're also going to need one heck of a lot of room. Not to scare you but, we're talking about a marine set-up on the order of 150+ gallons, absolute minimum. If this is beyond what you're ready to tackle, please, return them or find them a suitable home now while they're still juveniles.>> Jennifer <<Tom>>

Sharks <Arius cats> and a new tank 5/2/06 Hi, <Hello>   I have read quite a few posts but have not found an answer to my problem. Here it is. I bought 3 black fin shark <Arius...>, 3 platy and 1 Pleco (from Wal-Mart, not sure what I was thinking). After reading the little description card I take these guys home, set up their tank and put them in it along with two live plants. That evening they were ok but the next evening one was swimming upside down at the top of the tank and seemed to be gasping for air. I immediately cleaned the tank which seemed to be very dirty and placed them in a holding bucket and pumped air in thru an air stone. It seemed very happy and normal again. I went out and bought a filter, a thermometer, heater, and an extra air tube. I already had the aquarium salt and air pump. Well I moved them to a 10 gal tank and setup all of the equipment. Good...everything back to normal..... Until today, again this shark, now swimming vertical and gasping for air at the top of the tank but not yet upside down. I don't get it because the other two are not acting this way. They like swimming in the air bubbles and lurk around the bottom of the tank. I am on my way to purchase a second air pump because for some reason I think this fish is short on air supply. So my question is what in the world is going on with this shark or is this normal?? I've only had them for 2 days now and am very uninformed and now confused. Oh and they are only about 2-3 inches long right now.  I appreciate any advice or info you can provide.      Jennifer <The short answer is that the tank needs to be cycled.  Please consider returning the fish and waiting until the tank is properly prepared for them.  The long answer can be found here http://www.wetwebmedia.com/FWSubWebIndex/fwset-up.htm , http://www.wetwebmedia.com/FWSubWebIndex/fwtips4beginners.htm and perhaps most importantly here http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm >.  Good luck and with a little preparation I'm sure you will be successful> <Chris>

Black Fin (Ariid catfish) Sharks <FW?> Hello Crew, <Hi Greg, MacL here with you today> I love your site! I've been an avid reader of your website, recommended to me by our local salt water fish store, since I began work on my first salt water aquarium. My question pertains to 2 Black Fin sharks that I have in a 20 gallon brackish water aquarium. <<?>> I've had the sharks for about a year now and they are both about 4 inches long. They are very active and healthy.<That's great!> But reading on your site tells me that the 20 gallon will not hold them for much longer.<They grow soooo fast!> I also just read that they would prefer a saltwater environment once they get closer to adulthood. I have currently a 55 gallon saltwater with 60lbs of live rock, 2 1/2 inch sand bed, 1 Tomato Clown (1"), 1 Flame Angel, 2 Fire Fish, 1 cleaner Shrimp, 1 Sand Sifter Starfish, 1 4"Green Brain & a few frag corals all doing well. Water parameters in the salt water tank are PH 8.2, Salinity 1.024, Nitrates and Nitrites are 0. Can or should I add the 2 sharks to this environment? <You can but they most likely will eat your shrimp, and possibly your fire fish if the opportunity presents itself.> If I can, how long should I set up a drip to acclimatize the sharks to the saltwater salinity? <I would do it over as long a period as possible. At least 12 hours is my preference and if I could I would make it longer.  Slow acclimation is best.> <<RMF wonders if these are shark minnows... not cartilaginous fish>> Thanking you in advance, Greg Forrest

Sick Columbian Catfish   3/24/06 Dear WWM crew, <Hi, Pufferpunk here> Thanks so much for your wonderful website. I have learned a lot from it. <Great to hear!> I was wondering if you can help me with the following: I have 2 Colombian cat sharks each about 10.5 inches long in a 55 gal. tank. <Since they can grow as large as 18", I'd suggest a 90+g for them.> Other fish in the tank include 3 Monos and 2 Plecos. <Monos grow to about a foot & will require another 120 gallons.  Plecos have no place in brackish water at all.> I have been having trouble keeping the level of nitrates down and 3 of our scats died. <Scats too?  You don't mention the size of your fish but scats grow as large as a dinner plate.  All of the species you mention (except the Plecos) will require marine conditions as they mature.> I had the tank in the basement and decided to bring it up to the living room to better monitor the tank. When I changed its location I made a 50 percent water change to lower the level of nitrates. <50% water changes should be done on a weekly basis.> However, since we moved the tank one of the cat sharks has been sick. First I thought it was ich because I saw some little white dots. Now I am not so sure. <That does sound like ich.> Its skin looks almost like it has a thin discolored membrane over it. Its color is dull compared to the healthy cat shark; its body color has changed from gray-silver to gray-purple and its fin is always down. This morning I also noticed that the fin has a white spot and it looks raw and wrinkly. It almost looks like a fungus. He stays at the bottom very still and his eyes are clear. He seems to be breathing quickly. He has been in this condition for about 4 days. I have treated the tank with ich medicine, I changed some of the water last night (the nitrates are still high). <You should never medicate your entire display tank.  Sick fish should be medicated in a quarantine tank; so that all the fish aren't subjected to the meds, the disease isn't spread further, the fish isn't stressed by it's tank mates (because of it's weakened condition) & you don't do harm to your biological filtration with the meds.  That way you can also do large water changes on a smaller tank.> Also, I should say that one of the Monos had a sore in its mouth that I was treating with penicillin (4 days). Now the treatment has stopped and the sore is not as bad. So there was some penicillin in the water as well as ich medicine. The temperature in the tank is 73F, salt water level is 1.002, the Ph. 7.2, alkalinity moderate (80), hardness (very hard), nitrates 160 (still unsafe).   <Are you using marine salt?  The water is way too cold--should be 78-82 degrees.  To treat ich, you should raise the water temp to 86-87 degrees.  Your SG should probably be around 1.010.  Nitrates should be under 20.  Sounds like you haven't been doing enough regular water changes in there.  Are you rinsing the filter & cleaning the gravel regularly?  I should also mention that pH for BW fish should be around a steady 8, usually done by using aragonite or crushed coral as substrate.> I should also mention that about 3 months ago he jumped out of the tank and was on the floor for about 10-15 minutes before we found him. <Definitely stressful.  Stress=lowered immune system.> It took a while to recover and he was never as perky as before. He kept to the bottom of the tank most of the time but he was in good overall health. I really would appreciate your advice. I don't know what to do and it seems to me that time is running out for my "little" Colombian cat shark. Thanks a lot for your assistance. <Start out doing 20% water changes daily, until your nitrates are under 20.  Add Melafix for the shark's skin & the mono's mouth.  If there are still ich spots, raise the temp.  Keep adding marine salt, getting the SG up .002/week until it is around 1.010-1.016.  Continue doing 50% weekly water changes.  Find homes for the Plecos.  Start saving for a much larger tank.  By then, they should be ready for SW.  ~PP>

Ill Colombian cat shark ... Bob's go  3/25/06 Dear Bob, Thanks so much for your wonderful website. I have learned a lot from it. I was wondering if you can help me with the following. I have 2 Colombian cat sharks about 10.5 inches long in a 55 gal. tank. <A bit crowded...> Other fish in the tank include 3 Monos and 2 Plecos. I have been having trouble keeping the level of nitrates down and 3 of our scats died. <A bummer... need much more room> I had the tank in the basement and decided to bring it up to the living room to better monitor the tank. When I changed its location I made a 50 percent water change to lower the level of nitrates. However, since we moved the tank one of the cat sharks has been sick. First I thought it was ich because I saw some little white dots. Now I am not so sure. Its skin looks almost like it has a thin discolored membrane over it. Its color is dull compared to the healthy Catshark; its body color has changed from gray-silver to gray-purple and its fin is always down. <Bad signs> This morning I also noticed that the fin has a white spot and it looks raw and wrinkly. It almost looks like a fungus. He also stays at the bottom very still and his eyes are clear. He seems to be breathing quickly. He has been in this condition for about 4 days. <All easily just symptoms of nitrate poisoning> I have treated the tank with ich medicine, I changed some of the water last night (the nitrates are still high). <How high is that?> Also, I should say that one of the Monos had a sore in its mouth that I was treating with penicillin (4 days). <Uhh... you need to fix these fishes environment... too crowded, polluted... they don't need medicines> Now the treatment has stopped and the sore is not as bad. So there was some penicillin in the water as well as ich medicine. The temperature in the tank is 73F, salt water level is 1.002, <Needs to be higher for the Ariids at this size... remove the Plecos and raise>> the Ph. 7.2, alkalinity moderate (80), hardness (very hard), nitrates 160 (still unsafe). <Yikes... very toxic> I should also mention that about 3 months ago he jumped out of the tank and was on the floor for about 10-15 minutes before we found him. It took a while to recover and he was never as perky as before. He kept to the bottom of the tank most of the time but he was in good overall health. I really would appreciate your advice. I don't know what to do and it seems to me that time is running out for my "little" Colombian cat shark. Thanks a lot for your assistance. Anouk Patel-Campillo <Well, elevating the salt content (after removing the Loricariids) will forestall nitrate poisoning for a bit... but these Ariids and Monos need to be in larger quarters... at least twice this size... and to be exposed to no more than 20 ppm. nitrate maximum. End of line. Bob Fenner>

Columbian shark size   3/21/06 Hello.  I have 2 healthy Columbian sharks living in a 55 gallon tank.  They are about one and a half years old and about 7 inches each.  They seem happy and are doing well.  I was just wondering when they stop growing and how big they will get.  I've read in many places that they get to be as big as 14 inches but then some sites say only 6 or 7 inches.  Also, do you think I need a bigger tank? Thanks for the help! >> A friend grew his to 22" in a 65 gallon tank. They are really not good aquarium fish because of their size, sadly most pet stores do not even know how large Colombian Sharks grow.

Housing Silvertip (Columbian) Sharks  2/19/06 <Hi, Pufferpunk here> I have two Silvertip Sharks (catfish) and I need a bigger tank.  I was not smart and put them in a ten gallon aquarium.   <I can't argue with that!> They are healthy, eat well and have grown to five inches. I have been using aquarium salt.  Does aquarium salt make a tank brackish?   <Nope, for BW you must use marine salt & measure it with a hydrometer.  Start by adding enough salt (premixed) to raise your SG (specific gravity) .002/weekly water change.  As your fish grow, you will want to raise the SG to marine conditions--around 1.023.> I have an eighth inch of gravel on the bottom of the tank.  They cleared a corner of the tank clean of the gravel and like to sit there when not swimming.  When I get a bigger tank I want to slowly change them from a brackish aquarium to marine and want to know what decor is safe to put with Silvertips.   <For BW, I suggest using at least 1" of crushed coral or aragonite.  this will slowly dissolve in the water & buffer the pH, to keep it steady, around 8.>   I searched everywhere and could not find what decor silvertips get along with in a brackish water or marine tank. I found out on my own that live plants die in brackish water. Can they get along with coral or anemones?  I do not want much decor because they need lots of swimming room but I want something in the tank besides them.   <PetSmart makes very nice fake mangrove roots that emulate the natural environment they live in.  Fake plants, silk or plastic work well.  As these fish will eventually grow up to 18" & like to live in schools, I suggest planning on a very large tank.  I think a school of around 5 of them would be very impressive in a 90+ gallon tank!  ~PP>

Anaerobic digestion/Denitrator product input, Ariids in FW  1/8/06 Hello WWM crew. <Howdy> I have a few questions I cant seem to find the answer to. 1. http://www.aquaripure.com/index.htm this is the link to a filter that reduces nitrates in the water. Does this filter really work?   <Mmm, "can" but almost always doesn't is the fairest answer... folks don't keep up with feeding (a source of ready carbon, usually a sugar, sometimes an alcohol) to these units... and the claim re cutting back on water changes... fallacious is a nice adverb here> 2. I have a 30 gallon tank with a 1-redtailed barb,1-silver-tipped catfish and a 1-peacock cichlid. I know that the silver-tipped catfish needs to eventually be in brackish water. Will the silver-tipped catfish live his/her life span in freshwater conditions? <Mmm, a much fore-shortened one... the answer, no> 3. In the same tank as described in question 2, I am running two Marineland Emperor 400 power filters. The entire tank is recycled about 26 times per hour. Is this too much water current for the fish? <Nope> Thank you, your time IS greatly appreciated by all <Welcome. Bob Fenner>

Help - my fish are stressed... brackish/marine catfishes in FW  12/20/2005 Hi. I have a 55 gallon tank with live plants and plastic with lots of hiding places as well that has been established for 1.5 years. PH is 7.6 (I have been using Reverse Osmosis distilled water for 30% water changes weekly) with a Fluval 304 filter system. 3 - 3" clown loaches, 1 large angel fish, 3 small Bala sharks, 4 pictus cats, 3 small rainbow sharks. Two days ago we purchased 3 small Columbian sharks and today when I turned on the light it was flopping around upside down on the bottom of the tank and about five minutes later he <Who, what is "he"... one of the Colombian Sharks?> was swimming around (albeit crooked) I can't seem to keep my fish happy. About a month and we had a sudden spurt of fish dying every day with no signs of sickness. What else should I be looking for. Thanks for your help. Donna Wildeboer <Mmm, the so-called sharks are brackish to marine Ariid catfish... Please see here re: http://www.wetwebmedia.com/ariidcats.htm and the linked FAQs files above... You will see many folks have been similarly (mis)led. Bob Fenner>

Freshwater: Mystery Fish, New Tank (Transfer) and the Nitrogen Cycle 11/30/2005 I have 2 Silvertip Shark (Silvertip tetra) approx 4"not sure of the exact name, <Well the first name you gave 'silvertip shark' makes me think it is a catfish from the Ariidae family, which need brackish to marine environments as adults but the second name you gave 'silvertip tetra' leads me to believe it could be a tetra in the family Tetragonopterinae. But with there size being 4' I doubts it's the latter probably the first one I mentioned.> 1 Pictus Catfish approx 2"and 1 Chinese Algae Eater approx 4", all of them were doing well in a 30 gallon tank, I moved them all to a 75 gallon tank, I let the tank "set-up" for approx. 8 - 10 hrs, now only the Algae Eater is eating, the other 3 are not eating. <Understandable, a tank 8 to 10 hours old is not stable yet. Even if using filter media from the old tank I doubt it has cycled. Furthermore did you acclimate the fish to new environment or simply transfer them? They are likely stressed out.> In the 30 gallon tank the Sharks would attack the flakes that I would feed them, now they just let the food float and fall to the bottom of the tank, none of the fish have changed color have spots nor do they have any visible signs of illness. I had the water tested and it was fine. tank temp is set at 79 f.  I can't figure out the sudden change in the fish. <I would just give them some time. Offer a small amount of food maybe once a day, and don't be surprised if they go on a hunger strike for even a week or so period. However, in the mean time I would be testing your water vigorously because I am willing to bet you show some sub-par readings whether it be ammonia, nitrite or nitrates. If these are present be prepared to do water changes and perhaps look into some live bacteria cultures such as BioSpira. Search WWM re: 'freshwater nitrogen cycle.' I'm afraid this transferring of livestock was to sudden and far to premature. Adam J.> 

Columbian Shark Needs Friends  4/25/05 <Hi, Pufferpunk here> I have a question about my aquarium. It is 20 gallons now but will be upgraded as needed within a year. The only fish in the tank is one very friendly Columbian shark named Antonio. The poor guy wants a buddy; I'm sure by the way he follows my finger against the glass. The problem is if we get another Columbian we won't know who is who. Is there another catfish or shark species that will keep Antonio company while the tank slowly shifts to full saltwater? <since Antonio is actually a schooling species, he would be happiest with more of his same kind.>   Perhaps a mail order outfit is available for other brackish Catsharks? If the only species available are Columbian sharks, would a molly, orange Chromides or similar mid-water community type fish keep our little Columbian boy company? That is until Antonio eats this smaller fish! Thank you. <I'm glad you are planning on an upgrade in tank size & marine conditions.  A school of 18" silver sharks can be quite an impressive sight on their own!  Just make sure the tank is big enough.  ~PP>

Regarding Iridescent Shark, jumping into the hobby with both feet, sans even a nose-plug of needed background  10/4/05 Hello I recently purchased a used 55 gallon fish tank. The previous owner included 2 large Plecos (10in,12in) an Iridescent shark (8 in) as well as 6 school fish another small bottom feeder and a Gourami. <... the "shark" is a brackish to marine Ariid catfish> I kept the 3 large fish and gave the rest to a friend. Since the owner put the fish in a bucket with original water I was forced to get the water ready and let it run for a day before I put the fish in. When I brought the tank I changed the rocks and put a heater in. I guess my first question is should I keep the fish at room temperature as he did or heat the water to another temperature. <Please see WWM, fishbase.org or a freshwater aquarium book re each species... Needs to be thermostatically heated...> If I had any choice I would not have purchased the shark since I know they grow very large. My next observation is that the shark will not eat, the owner gave me shrimp pellets for the shark and freeze dried bloodworms. When I feed the fish the smaller Pleco eats the pellets up. The shark just swims right past them and the larger Pleco doesn't eat either unless he eats when I put the light out. Realizing that I will never know if the shark is truly eating I put the bloodworm larvae in the tank. It floated around for an hour and he did not eat it. When I woke up in the morning the larvae was gone so Im not sure if he consumed it or if it simply fell or was sucked into the filter. The fish hasn't ate in two days since I brought it home as far as I know. I wonder if I should maybe bring him a feeder fish to start his appetite. <... no> The fish are also giving off long stringy feces. Is this normal? <... depends on what they've been fed mostly> The smaller Pleco that does eat is swimming around with one of these strings attached to him. The shark looks very lively but he has white bubble coverings over his eyes, one being larger than the other. I am not sure if these are normal characteristics of this fish. I noticed that none of the fish have Ick (at least what I believe is Ick, small white spots on the body). I realize I should have cycled the tank for a few weeks before I put any fish in but the previous owner left me with no choice. <If you used old filter media, substrate, likely is/was cycled> I also realize the tank should have been populated with small hardy fish for a while after that before I put any bigger fish in. One more thing I noticed is the water became cloudy a day after I put the fish in. I would greatly appreciate any advice on how to care for the fish and if the shark will come around. Thank you             Marcin <Please... read on WWM re FW set-up, maintenance... trade the shark/cat into a store with another hobbyist with a brackish background, a marine tank to move it to. Bob Fenner>

Randomness (Ariid catfish, brackish maintenance) Hi again!  <Hi Rachael!> Sorry I write you guys all the time, but it's only because you give the most reliable advice around! I have an Arius Seemanni that I've written to you about several times and he's doing good, except that every few days he won't eat, I've tried everything in the store in regards to fresh food, (nothing live lately because it's hard to find feeder-type fish that will survive in a marine aquarium and that aren't in horrible shape like guppies and goldfish.) Anyhow, I have been feeding him raw shrimp and bay scallops for some time now and he used to go crazy over them, now he might eat one piece and then just continue prowling the tank, I have tried frozen krill and he shows absolutely no interest. Every few days he will just gorge himself on food and then the next two days he will just pick at it, is he just full? or is he silently complaining about the food? I know he needs a lot more variety, but I don't have the money to blend up a whole batch of vitamins and plants and fresh meat for one little fish, it would spoil too quickly, so I'm holding out on the big stuff until my tank cycles fully and I add more fish that will help him clean the plate (and clean up the mess he makes). He still readily eats flake food, but I know that's not the best for him so I only use it when I feel helpless. <Feed less, a little several times a day, only what he will eat in a few minutes. Net whatever he doesn't eat out of the tank, it's contributing to your water quality issues. Try freezing your prepared food blend in ice cube trays and thaw a small portion to feed. It's very common to overfeed fish and spoil water conditions, which then leads to more problems.> Ok! the next thing! My tank has had a relatively high nitrite level for about a week now, (I would normally assume that that's why the Silver Cat isn't eating, but his boycott of food is intermittent, so I'm not so sure) But how can I get these levels down? The ammonia is undetectable, and the PH is perfect, I know all the FAQs say Nitrobacter can't reproduce well until the ammonia is gone, but is it normal to take a week or more? I'm just worried about the long-term effects it might have on the catfish. I have added some live rock (I'm buying it piece by piece due to my extreme poverty -- that's the life of a student!) in hopes that it will help bring down the nitrites. The LFS said that water changes would be fine but really I have to just let this cycle out...What to do, what to do! <This indicates your tank is converting ammonia into nitrites. This is very likely contributing to the stress on your fish. You need to do water changes to keep this under control!!! It will "cycle out", but it will reach a level unhealthy or deadly to fish! Also, make sure the rock you add is well cycled.>  The last thing, I promise! I was reading some of your FAQs and I saw something about salt creep! I was stunned, there is even a name for what I'm seeing! All I ever see is warnings about not "salting-out" your fish, but what about all this salt that is getting away!? First of all, I know it's because of my pump and aerator, but I don't want to remove the aerator because there is really no other source of oxygen in my tank, the skimmer doesn't seem to be doing much in the way of oxygenating, so I didn't really know what to do. I don't like cleaning the salt all the time but if there's no other way then I'll just deal I guess! Sorry this email is so long! Thanks for your patience and help! Sincerely, Rachael <Remove the aerator, they don't do what you think. They produce slat spray which you see in salt creep. The skimmer oxygenates just fine. You don't want to see bubbles and they can actually cause problems. Hope this helps and you're doing well in school! Craig>

Arius catfish - 02/24/03 Hi there!  I Hope everything is well over there!   <Hi from Ananda today... > I'm writing about a Silver-tipped shark I have, it's about 5 inches long, in a 55 gallon tank, is this tank too small at this point?   <For a 5" fish, a 55 gallon tank should be okay for now.> He isn't really active at all during the day, at night he swims all around with the smaller silver tip I have, the smaller one however swims constantly, mostly near the "lair" they share, but he never stops swimming.  They are both living in a full-saltwater tank, I have heard that as they get older they do best in a brackish to saltwater aquarium and I was just wondering if this is right?   <I have read/heard this many times.> I guess I just feel that the larger shark is abnormally lethargic during the day, and I was wondering if it was due to the salt? <You could try varying the salinity a bit -- if you are at 1.025 now, see what happens when you drop the specific gravity down to about 1.020. I would drop the salinity by using less-salty water for water changes. But go slowly if you have inverts.> All the other fish act normally, the inverts in the tank are doing great -- the water parameters are ideal, what could be wrong with this guy, if anything? As he's gotten larger he's slowed down a lot, when he was little he was very active, so could it just be part of growing up for him? <It's possible.> Any thoughts would be helpful!   <How much water flow do you have in this tank? If your filtration doesn't have a lot of turnover, I'd consider adding a powerhead or two on one end of the tank, pointing at the other end of the tank. These fish are reported to like current.> thanks so much, have fun today! Rachael <You're welcome. --Ananda>

White tipped Shark Catfish/Columbian Sharks? Hi, I was just wondering exactly how long these catfish should be kept in freshwater conditions.  Currently our 2 are each an inch and a half long and living in a freshwater tank 75g with small amounts of aquarium salt added for general health.  At what size do we need to slowly adjust them to a saltwater tank?  (How long can we keep our little guys as I do not plan on getting a separate Salt water tank?) Thanks, Andy <Actually, unless the source water is quite hard and alkaline, this species should never be kept in straight freshwater... it's a brackish to marine species. Please see here: http://www.wetwebmedia.com/ariidcats.htm It can be kept in minimally (spg 1.005) to about full strength (spg 1.010) brackish water for years, but is better off in near seawater (spg 1.025) water when a few to several inches in length. Bob Fenner>

Columbian (Silver-Tipped) Shark  7/1/05 Hi, <Hi, Pufferpunk here> Sorry to ask a question with an answer that may be obvious to some but it's necessary.  I have been reading your site and it's definitely helpful, although I am still a bit confused on the right road for these "sharks".  Mine (two of them) are around 5" in length, and they just moved (as in TODAY) from a 10-gallon to a 55-gallon.   <Much better!> Now, before you yell at me, I have to defend myself by telling you that I bought them on a whim at Wal-Mart and had no idea that they'd get so big.   <Research before buying next time but I guess I don't have to tell you that now.> So, since I was waiting on a hand-me-down 55 from my friend, the sharks resided in a way-too-small 10.  In this 10-gallon, they were starting to get very uncomfortable, I know and swam weird patterns, I suspect because they were so big and didn't have hardly any swimming space.  Now that they're moved, they don't seem to be happier.. I read about fish coming from tanks too small that hang on the bottom for a while or maybe it's the relocation that has them confused.  They seemed to be swimming more as of a minute ago but they were just lying on the bottom together, looking out the front.   <Maybe they were franticly looking for more swimming room in the smaller tank.  Now that they have the room, they can take the well-deserved rest.> I should also comment on their water.  As these were fish-whims, they were always in freshwater with regular aquarium salt and up until a few months ago I had no idea they were supposed to be transitioned to brackish or saltwater.  I guess my question is, after you hopefully give some answers to the questions posed already in this run-on query, are they supposed to END UP brackish or completely saltwater?  I have read that you are supposed to "slowly add more salt" but for a 55-gallon, how much and how often?   <You'll need marine salt & a hydrometer to measure it.  Start raising the SG (specific gravity, measured by a hydrometer), .002/weekly water change, until you reach around 1.010-12.  Eventually, as they grow to 14-18", they will need a much bigger tank & marine conditions (1.020-24).  You should premix the salt in a bucket, before adding.  It'll take some math to figure all this out.> Also, can other types of sharks live in this water, whatever it ends up?   <The sharks you have, are the only BW "sharks".  Since they are actually schooling fish, more sharks would be welcome but you are talking about eventually a huge (50g ea) tank!  I'm sorry these fish are even sold at most LFS, as there are very few folks willing to house these fish properly for life.  Most will die a slow, miserable, stunted death...> The person at the pet store told me that any semi-aggressive can go with any other semi-aggressive and I'm guessing that's not the case.   <These fish are not aggressive at all but are predatory & will eat anything they can fit into their mouths.  They are constantly on the move (most of the time), so they cannot be housed with mellow, shy, slow-moving fish--the sharks will stress them out & outcompete them for food.> Should I choose tankmates, if I upgrade to a bigger tank, based on water as well as compatibility? <Yes, pick BW fish that will eventually transition to SW as adults.  More of the same species sharks & scats would work well, but again, figure eventually needing 50g/fish.  A school of these sharks can be quite impressive!  ~PP> Thanks, Kate

Arius advice Hi my name is Doug ,could you please give me some advice .I have a 6x2x2 tank and at the moment have got 3 Arius seemanni 1 at 6" and 2 at 5". <Be careful with these marine catfishes... you likely know they can be painfully venomous... Please read: http://www.wetwebmedia.com/ariidcats.htm> I have the chance to buy 2 more at 6/7".ive been told that they will not reach a foot in length so 5 Arius in the tank would be ok ,but I've seen a few mailings on the web tonight of people having Arius of 14" .obviously if they grow over a foot I will just keep the three as the fishes well-being is most important thanks  <They grow slowly as they approach maximum lengths... Having five in this size, volume system should pose no difficulties. Bob Fenner>

Catfish Problems Hi, I've been reading the FAQ's and you all are great. I have just a quick question. I'm pretty sure I know the answer but want to make sure. Yesterday I adopted some fish, lady was going to flush if she had to, 8 fish. 3 young rainbow sharks, all under 3". These I know I have to separate. Well she also gave me 5 Arius seemanni. Ranging from about 4" to about 7". I do not have a marine tank to house them in, and they have been living fw with low salinity for a while now. I'm quite sure I need to place these fish elsewhere, but wanted to make sure that was my only option.  <this fish may live for many years in an appropriately sized tank (large) in brackish water> If it is, can you recommend a true fw catfish that's active and will do well in an alkaline tank (its my African. cichlid tank). Thanks for all the help <the problem with catfish and African cichlids is as much finding a species of cat that is tough enough for their aggression. Not many natural choices. However, various Synodontis species (not all but many) will fare well. Popular choices include the Featherfin, lace, angelicus, schoutedeni species. Really many more... do review the members of this genus. Best regards, Anthony>
Re: Catfish Problems
Thank you for the advice. I will be placing the A. seemanni, as I do not have anywhere for a large enough tank for them to be happy in. And I think the Angelicus will do well with my Africans. Thanks again:) <always welcome my friend! And a fine choice with the Synodontis angelicus... a magnificent catfish! Anthony>

Brackish to Marine Hi, I have three A. seemanni (sp?) <Hmm, an old (nomen nudum) name still in use by some. See here: http://www.wetwebmedia.com/ariidcats.htm and here on FishBase: > sharks and I would like to place them into my marine tank. The Sharks are in a salinity of 1.01 and the marine is at 1.20-23. both ph and temp. are the same. Would I just raise the sharks up to the marine?  Or lower marine tank slightly and raise the sharks up slightly?  <Slowly... should be done over a period of about a month (or more) to limit stress, damage (mainly to kidneys)...> One is about 8" and the other two are about 6". Are they too old to be full marine now.  <S/b fine> I had a bad experience about a two years ago trying to get some to full marine and they were about 12" and the salinity was raised over a period of about 8 weeks. They seem to be ok and all tests were fine but with the last increase They started to die. just stopped breathing. <Bizarre... and frightening.> I saved one out of 5 by placing them into a fresh water tank. So I am very unsure if I should even try with these. They would have a lot larger area to swim if I could move them. Thanks for any suggestions. Robyn <Do take it slow... and keep a close eye on them. Bob Fenner>

New Tank Stocking Hi I need a little information, if you don't mind. <It would be my pleasure.> I have a 10 gall tank, with 2 Arius seemanni, when I bought them they called them high bull fin sharks. <Call them what you want, these fellas are monsters.  Check out fishbase.org, search for Tete sea catfish for more information on these fish.  I'd take them back to the store and slap the guy who sold them to you to put in a 10 gallon tank.  They will grow to be around 13 inches.> I have tropical fish pellets, 2 red tetras, and a bottom feeder.  I am confused on what to do for these fish.  I am reading that they are really salt water fish and they eat live food and will eat others in the tank. <If your tetras start disappearing, you will know why.> I also am not sure about what kind of tank I need, what about ph and what about mouth brooder what is all of this? <pH 6.0-8.0, brackish water would be best for long term health.  Mouth brooders rear their young in their mouth.> I am a beginner and in need of help.  I have had these fish for 3 hours and I am feeling as if I am way in over my head. <I would reconsider these catfish they are going to need a much larger tank, and brackish water.  There are some delightful tetras out there, maybe offer a trade at the store you purchased them from.  I love my black neon tetras.> Also I am wondering what could be wrong with one of these seemannis it has a swollen belly does that mean it is pregnant or has eggs?? <Probably not.  Missing any tetras?> Thank you so much if you take the time to answer these questions. <No problem, we have a ton of good reading out our site, I'd recommend starting at the link below.  Best Regards, Gage http://wetwebmedia.com/FWSubWebIndex/fwset-up.htm >  

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: