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FAQs about Ariid Catfishes, aka Columbian, Silver-Tipped-... "Sharks" 2

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, Brackish Aquariums The (Iridescent) Shark or Eat-em Up Catfishes of the Family Pangasiidae & Pangasiid FAQs,

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

Columbian... Shark Catfish... a brackish (when young) to marine... yes full saltwater... species as large/r adults.

Columbian Shark Catfish; gen. and fdg.      7/31/15
First, I want to say thank you for all you have written on your website regarding these majestic creatures. With that, I'm having a ton of issues and could really benefit from your expertise....
<Let's see>
First, I purchased this catfish Shark from Wal-Mart. How awful,
<How I wish that non-specialized mass merchandisers would either get out of the livestock trade/s period, OR at least get someone who knows to pick species that are suitable for use.... this fish, Green Spotted Puffers.....

I knew nothing and was ill equipped to handle this. So to make a very long story short with the specific issues at hand ... I have 2 left. I will upgrade the size of the tank when I know I can keep them alive.
<Oh! Neale and I and others have most all the pertinent husbandry  facts/FAQs archived (READ) here:
Brackish animals when small; full saltwater and large later>
I purchased a sub pump for my bow front 30 gal along with a bio filter and I aerate the water 1/day now. I have increased the salinity to 1.0005-6 in the last month but I can't get the water clear again.
<Be patient here>
I called instant ocean customer service and did what they said, but maybe I need to use more purified water, not just dechlorinated?
<The dechloraminated water should be fine>
I learned that they prefer sand, so, unfortunately I mixed some sand in the water And created a huge mess. Can I, while the tank is still going, scoop out the gravel and sand and add the aragonite for brackish water ranks?
<Yes; though perhaps better to siphon out over a few maintenance cycles and  replace>
Or should I start with a whole new set up?
<I would not>
My biggest issue is getting them to eat....they wouldn't take any of the pellet/flake/commercial food. I've bought scallops, whitefish and tilapia.
They finally ate a little of the latter provided a microwaved it for 13 seconds...they wouldn't eat it raw, and they wouldn't eat it cooked.
<No to cooking foods for fishes>
I tried canned Salmon, sustainable tuna,
<Don't use these... too messy; polluting>

and baby shrimp. They ate a few baby shrimp a little the first day, but none following. I bought red minnows (6), thinking live food might help, but, alas, I now have 6 very fat feeder fish. I bought 15 ghost shrimp, because, I thought, they ate the first 3 I purchased, but its like they just don't see them. They do smell them, but don't catch them. Then I bought black worms (which she told me to rinse out and keep in the fridge, and I think are dead now), and, they ate them, IF that skinny little worm hit them on the head...otherwise they are oblivious. And now, 2.5 days later, they are not eating them at all and I
have a blanket of worms on the floor of the tank, which, I don't know if are alive or dead. They stay in one spot waiting to be fed...I've tried chicken, seasoned and raw, and roast beef organic cold cuts (without success).
What do I do?
<Siphon out the mess; test for ammonia, nitrite, nitrate....>

I have to go away for a couple of days and I don't even know how to get someone to feed them if they won't eat.
<Don't worry re... unless very small, thin they won't starve in your days absence>
It makes me neurotic.
Please help. thanks
<The reading when you have time, can make yourself calm. All will be revealed. Bob Fenner>
Re: Columbian Shark Catfish     7/31/15

And I also wanted to add...
What about Cichlid lake salt instead of instant ocean?
<Synthetic sea salt is better... the IO or another brand>
It would seem that better for brackish conditions....since these are brackish fish like cichlids....
<They are not.... salts are combinations of metals and non-metals chemically/physically. There ARE many types/kinds of salts. The ones that make up the mix of the Great Lakes of Africa that some manufacturers offer are NOT the same blend as seawater... which IS where Sciades hail from. BobF>
Re: Columbian Shark Catfish        8/1/15

So stay with my instant ocean?
<As stated>
Can you recommend anything else for me to feed them?
<Small meaty foods, in moderation>
I've read and reread your archives, but I can't get them to eat regularly....
<Tis the environment.... needs to be/come established. Do you have friends who might come by, speak with you re aquarium set up?>
And buying a can of baby shrimp for 5 and throwing the rest out is very expensive....
Re: Columbian Shark Catfish... /Neale        8/1/15

So stay with my instant ocean?
Can you recommend anything else for me to feed them? I've read and reread your archives, but I can't get them to eat regularly....
And buying a can of baby shrimp for 5 and throwing the rest out is very expensive....
<Can I direct you to some reading?
Not difficult to keep in brackish or marine systems. Need a varied diet, but a standard carnivore catfish pellet makes a good staple, alongside white fish fillet and *occasional* mussels and prawns (these two shellfish contain too much Thiaminase, and cause all sorts of problems if used to excess). Gregarious, peaceful, but predatory, these are excellent fish in the right system. Cheers, Neale.>

black fin shark from Wal-Mart     1/11/14
ok I just bought a black fin shark from Wal-Mart. it was the last one they had and I am a sucker for lone fish. the question I have is mine is doing unbelievably well. he has a good appetite and is very energetic. I have him in a tank with guppies, neon tetras and even Bettas 2 male and 3 female along with others and they all get along. I know black fins are brackish water fish and the fish I have it with aren’t but because it was suggested that even freshwater fish can benefit from a little salt in the tank I added some salt. maybe a small pinch of aquarium salt per a gallon. is this enough salt for a black fin or should it have more salt. I know the fish I already have did great with more salt content but I had to lean it out because  of a bad red algae bloom that wouldn't die. finally killed it off but it made a mess of the tank. any help would be appreciated.
<Hello Jeffrey. Let me first direct you to a couple articles:
It's true that Black Fin Sharks (more often called Colombian Shark Catfish here in England) can do well in freshwater for a long time. Juveniles probably grow up in rivers before heading out to the estuaries where the adults live. In my experience, I've seen many specimens in freshwater up to 5-6 inches long doing perfectly well in freshwater tanks, even as singletons. So your results with this catfish are by no means unusual. However, there inevitably comes a point when the migratory instinct kicks in and you see these catfish anxious to swim into brackish water. Such catfish spend their time "treading water" at one end of the tank, usually near the filter, and look distinctly frustrated I suppose if they can't swim somewhere else. Furthermore, as these catfish age, they become more prone to disease when kept in freshwater, particularly things like fungal infections. Put another way, while your singleton probably isn't unhappy at the moment, in the long term you do need to accept that this is a very big (expect 12+ inches), very predatory catfish that will eat all your other fish anyway (anything smaller than, say, 3-4 inches), and will eventually need an aquarium tailored to its specific needs (75 gallons at least). Some folks keep them in their own brackish water aquarium, perhaps alongside some Monos, Scats, Archerfish or whatever, while others opt to keep them in a marine aquarium with colourful but hardy marine fish such as Damsels, Morays or Lionfish that aren't difficult to keep. Either way these are spectacular fish -- a school of adults is about as close to real Sharks in the home aquarium as most people will ever get -- and well worth a little extra effort. Hope this helps, Neale.>

Black Fin Shark, Sciades seemanni? gen.   8/19/10
I just got a black fin shark and I want to make sure I am caring for it properly.
<By "Black Fin Shark" do you mean the catfish Sciades seemanni? I assume so. That isn't a name we use in England, but Google would suggest that a Black Fin Shark is this catfish. Silvery, white tummy, long whiskers, white tips to its smokey-grey fins, very shark-look in appearance.>
Basic information would be super helpful.
<As I hope you realise, this is a brackish water to marine catfish and CANNOT be kept in a freshwater aquarium. The ideal salinity for juveniles is around 20-25% normal marine salinity, i.e., SG 1.003-1.005 at 25 C/77 F.
Once the fish are more that about 10 cm/4 inches long these catfish need to be moved to somewhat more saline conditions, ideally SG 1.010 or higher, and fully marine conditions once the fish are fully grown, i.e., 20 cm/8 inches long. Sciades seemanni is a gregarious species, and single specimens pine and usually remain nervous and clearly unhappy. Keep at least three specimens, and ideally more. Tankmates should be large but peaceful; Sciades seemanni is easily scared and despite being armed to the teeth -- literally! -- it is easily bullied and tends to be terrified of things like cichlids, puffers and triggerfish that harass them. They are predatory though, and have a venomous bite that makes them easily able to kill small fish and shrimps, so choose tankmates with care. Fish the size of Sailfin mollies upwards should be fine. They also have venomous dorsal and pectoral fin spines, so take care handling them.>
Some of my questions are:
How many times should it be fed a day?
<As with most predators, a single meal a day is ample, and skipping the odd day will do no harm. On the other hand, a couple of small meals per day is fine too.>
Does it eat tropical fish flakes?
<Sinking pellets, yes. But this should be augmented with strips of tilapia fillet, cockles, and the occasional prawn or mussel.>
When should I turn the light off/on?
<They couldn't care less.>
How often should I clean the tank?
<As with any other aquarium, a 25% water change every 1-2 weeks is recommended.>
Also, I put a pinch of table salt into the 1 gallon tank, will that kill the shark?
<Table salt is NOT a substitute for marine salt mix, which is what you need. For juvenile Sciades seemanni, SG 1.003 is fine, and that's equivalent to 6 grammes of marine salt mix per litre, or about 0.83 ounces per US gallon. Table salt contains additives that may be toxic to fish and should not be used. Common aquarium salt is acceptable in the very short term, a few weeks, but for any degree of success with this fish you need the same salt as that used in marine aquaria, brands like Reef Crystals and Instant Ocean for example, or the generic own-label marine aquarium salt at some larger pet stores.>
Thank you so much for your time.
<Do please read here:
These are LOVELY catfish, and probably the most shark-like fish in the hobby. They are peaceful, hardy, gregarious, and beautiful to watch. But sadly they are grossly abused in the hobby, and treated as freshwater fish by unthinking hobbyists and disreputable retailers. Do make sure you understand the needs of these big, essentially marine catfish. Cheers, Neale.>

Re: Black Fin Shark, beh.    8/20/10
Thank you so much. The information is extremely helpful. Do they sleep?
<Naturally, like all fish. Groups rest up together in the corner of the tank. Unlike most catfish, Sciades are active during the day as well as the night, so they tend to take catnaps throughout the 24-hour cycle.>
Thanks so much,
<I assume this catfish isn't in a 1-gallon tank anymore. 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?
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,
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:
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:
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. Than 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.>

re: Sciades seemanni and Mono Questions (RMF, Pterois/Dendrochirus in brackish water?)<<No>>    3/7/10
I wouldn't have the space for lions, eels, and Monos.
<Oh, I see.>
I really like Monos and would want a bunch of them.
<A good approach. If you can, add a Scat or two; the combination seems to break up some of the tension that exists in schools of just Monos, possibly by providing a "threat" of some sort that stops any of the Monos becoming secure enough to feel dominant.>
Additionally, I want the estuary look and I don't think you would find Lionfish and snowflake eels there. I may be mistaken, but do they ever wander into river openings?
<I have read reports of Dendrochirus in brackish water, specifically Dendrochirus brachypterus and Dendrochirus zebra, but I don't know if they ever become resident in brackish water for long periods. Certainly both Pterois and Dendrochirus tolerate relatively low salinities (SG 1.018) indefinitely, and technically, that's brackish water, but I wouldn't ever recommend keeping them in a "true" brackish water system at SG 1.010 or less. On the other hand, there are various truly brackish water
Scorpionfish of various types, some of which are traded: Notesthes robusta, Neovespicula depressifrons and Batrachomoeus trispinosus in particular. Of these, Neovespicula depressifrons is wonderfully active and easily tamed, but at only 10 cm/4 inches once mature, might not be completely safe with substantially larger predatory fish. Being venomous, the danger would of course be to both predatory and prey!>
I bought 2 small Sciades Seemanni and began acclimating them overnight.
When I woke up the next morning they were swimming upside down with bloated stomachs. It appeared that the bloated stomach was buoyant and caused the upside down swimming. I let them go into the main tank and the lion decided to try to make a meal out of one (I knew this was a risk, but the cat was upside down and not swimming normal so he was extra vulnerable). I put the other cat in a quarantine container within the tank. His stomach seems smaller now and he is no longer swimming upside down. He looks better and time will tell if he will get back to normal. Is this a normal reaction to being acclimated to saltwater? Thank you.
<Were these freshwater catfish being adapted straight to saltwater conditions? If so, yes, it's quite common for some species to have problems with equilibrium. The swim bladder has to change to match the different density of seawater (which is more buoyant) compared to freshwater. Should be fine within a few hours. Catfish are physostomus, meaning they need to "burp" out the excess gas from their swim bladders. More advanced fish like Monos are physoclistous, and can absorb excess gas directly into their bloodstream. Cheers, Neale.>

Re: Sciades seemanni and Mono Questions  3/8/10
So the other Sciades Seemanni did die.
<Sorry to hear that..>
The bulge in his stomach went away and he was swimming fine for a day. Then the reverse happened, his stomach started to look sunken in. One hour he was fine and dead the next. I think it was due to the quality of fish.
<Possible, or else it was maintained in freshwater conditions for too long.>
I made the mistake of buying the fish at PetSmart. They must have had problems before I got them home.
<Does happen. Like many brackish water fish, if maintained in dirty water, or kept in soft water conditions, these catfish can become very weak. Look for lively specimens with bright colours, especially white bellies, and avoid any with sunken eyes or unusual dark patches.>
A couple days ago I went to a better fish store and picked up a new catfish. I acclimated him over 10 hours and he and the original cat in my tank are doing great.
The big cat I have had for 2 years is tons more active and you can hear both fish grunting.
<Neat, isn't it! Do look at the upcoming 'Conscientious Aquarist' that should be up on this site within the week. There's a whole article on the Ariidae catfish. Some scientists believe these catfish are not just communicating, but echolocating, like dolphins.>
Thanks for the help!
<Cheers, Neale.>

Columbian shark... gen., no ref.?  - 10/01/2009
I have a Columbian Shark.
<Sciades seemanni. A lovely brackish to saltwater catfish, unfortunately widely sold as a freshwater fish. Cannot survive in freshwater indefinitely, and certainly not healthily.>
He is very active in the aquarium, but I have noticed that he is always up the surface and is always keeping his mouth open, like he has something stuck in it or like he is "sort of" out of breath but the aquarium is very
well filtered and has also a very good airflow.
<When kept in small tanks or freshwater tanks, these catfish are notorious for "pacing" at one end, as if trying to get out. Would seem to be related to their migratory instinct. Wild fish may live in rivers as youngsters for a few weeks or months, but eventually they congregate in estuaries, usually in large groups. So, the aquarist needs to ensure the tank is big enough (at least 55 gallons) and equipped with a good strong current (6-10 times the volume of the tank in turnover per hour). The aquarium MUST have
brackish water at least SG 1.005, and as the fish mature, that should really be increased to around 1.010. Sub-adults above about 15 cm/6 inches can be kept in marine aquaria, and that is perhaps optimal, though let me mention here I haven't found them compatible with Puffers or Triggers, so choose saltwater tankmates carefully. Groupers, Snappers and the less aggressive medium to large-sized Damsels would be sensible choices. Adults get to at least 20 cm/8 inches when mature, and potentially 30 cm/12
inches, though that's uncommon in aquaria. They are gregarious fish, so keep at least three specimens, and ideally 5 or more. Singletons are very, very unhappy. They're very peaceful fish, and easily bullied, and quite
obviously lonesome on their own.>
We tried to take a look by entering the small finger in his mouth and nothing seems to be stuck there.
Can you please guide me of what the problem might be?
<Very likely how you're maintaining this catfish. Contrary to what the pet store told you, it isn't a freshwater catfish, can't be kept singly, and is too big for a small aquarium.>
thanks a lot
<Hope this helps. These are among my *very favourite* aquarium fish, and surely the most shark-like non-shark in the hobby, right down to the way they swim. But sadly, there's much misinformation out there on their requirements. Cheers, Neale.>

Columbian Shark... beh... gen.... no ref...!?  4/27/2009
Hey crew! Hopefully you can answer my question... I had a Columbian shark for the last two weeks.
<Sciades seemanni, a fantastic fish. But remember, it's a SCHOOLING BRACKISH WATER fish, and cannot be kept either singly or in a freshwater aquarium.>
As any Columbian shark we was very active going always up, down and around my tank. He was about two inches long. Yesterday I woke up to find my shark very slow, barely moving, kind of sad :( He didn't react to the food I threw him nor Anything I did for him.
<Oh dear.>
I went to the pet store were I bought him, the guy told me to change 50% the water.
<What is the salinity of the water? Sciades seemanni needs at least SG 1.005, and adults do best at anything between SG 1.010 and fully marine conditions.>
I did everything as careful as I could. I even changed the filter.
<Why did you change the filter?>
It's frustrating because I woke up this morning to see him dead! The strange thing is his dorsal fin was RED. I mean, RED! don't exactly know what that means... Did I poison him?
<We're you keeping him in a brackish water aquarium?>
Was he eating enough? Don't know! What does the red fin means?
<Could mean all sorts of things, but typically a secondary bacterial infection brought on by poor water quality or the wrong water chemistry. I cannot stress how important it is that these fish are kept in big aquaria (55+ gallons) with very powerful filters (they need strong water current) and a reasonably amount of salinity.>
I know he wasn't being bother by the other fishes, I had him black pebbles, sand under the pebbles, couple of plants, strong current, new filter even a really cool air pump thing, jeje, lots of the common suggestions....
Where I failed...?
<These fish are very hardy in brackish water aquaria; they cannot live in freshwater aquaria.>
Help me please... I think I want another one.
<Schooling fish, must be kept in groups: three or more specimens!>
He was the star of my tank... :(
<Yes, these are spectacular fish, and in big brackish water systems "steal the show".>
Sent from my iPhone ;)
<Sent from my Mac.>
Joanne M.
<Cheers, Neale.>

Colombian sharks, shark catfish, Arius jordani... Mis-placed, crowded, not-fed, not referred to the FAQs!!! - 08/16/06 I have a question about the Colombian shark or the catfish shark. <<Okay. I'll correct grammar and spelling as we go. (Bob gets a little "testy" when posts aren't decoded. ;) )>> <Heee! More than just a little... RMF> Mine are still young. I have had them for less than a week. I'm putting little tetras in but they seem to be too afraid to eat them. <<Juvenile Colombian Sharks haven't yet developed their predatory instincts. At adulthood - give or take - anything that will fit in their mouths will be potentially viewed/tried as food, however.>> They would follow it for a while but not really attack it. I still feed them flakes every now & then. <<Please research the diet your fish need. They're not overly picky but definitely need more than flakes to live, and grow, on.>> I have 3 in a 10 gallon tank and I will buy a bigger one when the time comes. For now, it's way too big for them, which is good. I want them to grow. <<They will, until unseen damage/under-development starts taking its toll on them. In about the time that it will take you to set up and completely cycle an appropriately sized aquarium, these guys/gals will need to be moved. A couple of months, three maybe and four at the most. You might also start, if you haven't already, acclimating them to brackish water conditions with marine (not aquarium) salt. If this is "news" to you, you've got homework to do since these are absolutely NOT freshwater fish.>> I put insects in for them and they don't eat them either, just a few bites then ignore it. <<This I like, diet-wise. Live insects are definitely on your Colombians' menu. Again, they're young so if they seem finicky about what they will, or won't, eat, don't be too concerned.>> Are they scared because they are still young, or what? <<Not scared but certainly tentative. Still feeling their way, so to speak. Be patient with them and, with good care, you'll watch them develop to their full potential. (P.S. Don't re-write the book because it doesn't "seem" to make sense right now. Far too many of these fish (most, I would say) die because the aquarist is misinformed, uninformed or simply doesn't want to buy into what knowledgeable people tell them. Do consider upgrading your tank in the very near future.>> Thank you XywiX <<Glad to help. Tom>>

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>> 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> 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

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.

How to move big Colombian catfish  12/15/05 Hello. I appreciate all of the info on your web site and spend hours reading it. Here is my problem: One of my eight tanks is a 75 gallon brackish (SG about 1.013) with a trio of 8-9" Colombian catfish (Hexanematichthys seemanni); the oldest one is about two years old. They all look fat and healthy and, of course, just keep getting bigger. They're quite beautiful and impressive. <I'll bet... a gorgeous fish at this size> I haven't yet decided whether to move them to a bigger tank with better filtration and a skimmer (I planned to take them up to or near full marine) or to trade them in at a knowledgeable local store that sometimes handles brackish fish and has agreed to take them. Either way, I have to move these fish out of their current home. How should I go about catching such large, powerful, jumpy fish without injury to me or them? Every time I clean the tank I worry about getting speared, and they have a tendency to bang into the ends of the tank and scrape themselves on the filter intake tube when alarmed. Thanks in advance for any advice you can provide. --Brackish in Tampa <I would (carefully) drain the tank down, remove decor, heater... and scoop these fish out one or two at a time in doubled fish bags of good thickness (4 mil)... pouring some/enough water out to not tweak your back in the process. Do take care to "not get poked" by their spiny dorsal and pectoral fin rays (as you state...). Bob Fenner>

-Columbian Shark Problems- Hello there, <Hi> I've recently tried adding Columbian Sharks to my 25 gallon tank with no luck. After a few days, they seem to change from black to grey. They look like they almost get a whitish coating and have trouble breathing.  <yes sounds like you tank water quality might be off. Check the Ph, ammonia, nitrites, and nitrates.> In the tank with them are a couple of guppies, some Tetras, a small white catfish, and two little frogs. Everyone else seem happy. My tank is about a year old. Any ideas as to what might be happening? What conditions do the sharks like best? Thank you for your help! Sylvia <Yes Columbian Sharks are a brackish water species that prefers a salinity of 1.005 to 1.008. If you choose to keep them, you need to keep them in a separate tank as the other fish are not brackish water fish. the reason the sharks are dying is because of the tank quality being off a bit probably and the sharks being brackish water fish. Good Luck. Justin (Jager)> 

Iridescent Shark 7/19/05 Heya Bob. I have 2 iridescent sharks in my tank. I know it is a very bad choice of fish for a small aquarium but since they are already living there for so long, I cant bare to kill them. Besides no one wants such a huge fish. I realize they are super hardy fishes. They got Ich and killed whatever was in the tank but survived the ordeal. However their noses were badly injured and did not recover after 1 year. They are rubbing their noses against the glass tank as if to swim thru it. The skin on the nose is GONE and I can see the red flesh and whitish stuff (perhaps the bone?). The other shark has a red pus on it. Sort of like a pimple that is about to burst, very red and in a bag. What can I do to treat their condition? Very heart-aching. Thanks and I look forward for your advice. >>>Greetings! Jim here. You've neglected to tell me how large your fish are, and the size of your tank. Quite frankly I hate to read emails like this. Am I to understand then that you can't bear to kill them, but you have no problem keeping them in such cramped surroundings that they cannot remain healthy? You can help then along with antibiotics, but frankly this will not be enough. You need to find homes for your fish, and stock your tank with appropriately sized animals. Cheers Jim<<<

Iridescent Shark 7/20/05 > Heya Bob. > I have 2 iridescent sharks in my tank. I know it is a very bad choice of > fish for a small aquarium but since they are already living there for so > long, I cant bare to kill them. Besides no one wants such a huge fish. > I realize they are super hardy fishes. They got Ich and killed whatever > was in the tank but survived the ordeal. However their noses were badly > injured and did not recover after 1 year. They are rubbing their noses > against the glass tank as if to swim thru it. The skin on the nose is GONE > and I can see the red flesh and whitish stuff (perhaps the bone?). The > other shark has a red pus on it. Sort of like a pimple that is about to > burst, very red and in a bag. > What can I do to treat their condition? Very heart-aching. Thanks and I > look forward for your advice. >>>>Greetings! Jim here. > You've neglected to tell me how large your fish are, and the size of your > tank. Quite frankly I hate to read emails like this. Am I to understand > then that you can't bear to kill them, but you have no problem keeping > them in such cramped surroundings that they cannot remain healthy? You can > help then along with antibiotics, but frankly this will not be enough. You > need to find homes for your fish, and stock your tank with appropriately > sized animals. > Cheers > Jim<<< Hello Bob Sorry about the missing details. Thanks for the advice <Welcome... have you read our accumulated FAQs re this species: http://www.wetwebmedia.com/ariidcatfaqs.htm and the linked files above? BobF>

Re: Iridescent Sharks 7/21/05 Hi Bob. Yes I did do a search using the search engine found in the web for iridescent, shark and nose. Read the articles with the combination but I did not find one that describe the condition or the suitable treatment. So I emailed you regarding this. Maybe the articles are dated too far back cos I did not go thru all the results from the search engine. I have also read the FAQ, FAQ2. <... so, these animals are in brackish to a marine setting... 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

Killer Catfish? Thank you! You really put my mind at ease. I love my 3 aquariums even if they got a little neglected when I had a baby last August (never to the point of bad water or disrepair, just not as diligent as I had been). Now that I am turning my attention fully back to my aquatic pets, I have one more question and I'll leave you alone. I have done a lot of research on this, but haven't come to a conclusion. I have an unplanted 55 gallon tank with two 330 Penguin BioWheel filters with a 4.5 year old silver tip shark catfish (Mack the Knife) and a large Pleco (Rainbow Barrone, Jr.). He had been coexisting with one Oscar who succumbed to old age. My husband was pretty heartbroken by Salvador the Oscar dying, so he didn't want another one. I got a Jack Dempsey, but Mack apparently killed him one night in a territory dispute. Short story long, is there any other species that would be compatible with Mack, or should I just leave him and Rainbow in there alone? < If Mack is going to kill all the new fish then I think leaving him alone is the best way to go>  Also, I've noticed Rainbow sucking on Mack lately. Is this a harmful practice? Should I separate them? Mack doesn't seem to mind as he just lays there. Thanks again! < Plecos have mouth parts for scrapping algae of things like rocks and wood. They will also scrape the protective slime off fish and can be a problem for fish like discus and angels. Little Cory cats on the other hand are just looking for bits of left over food and are harmless.-Chuck>

Iridescent sharks flipping out Hello, My name is Ted and I'm from NJ. This is the first time I'm submitting a question on this site though I've been on it many times. I think you guys are awesome and really appreciate all of your help and knowledge that you share. Thank you.  Ok, here's my problem.  I have two quite large iridescent sharks, one about 9" and the other about 12". I have recently moved them into a 72 gallon bowed front tank. Health wise they seem to be doing fine but they are getting spooked very easily. I've been leaving a couple of bags of gravel on top of the canopy because I'm afraid that I'm going to find one on the floor one day. <Good move> I have a feeling that being that its a bowed front that any outside objects or light might be making them flip out. <Possible> I never had a problem with them in their last tank. Though they were with other fish, and the tank was highly over stocked. (the two sharks, an Arowana, a parrot, a silver dollar, a Pleco, a clown loach, and a golden algae eater in a 90g) Obviously you can see why I moved them. I don't know, maybe its the tank, or maybe its the lack of aquatic friends. What do you make of it? <Mmm, the crowding and shape of this tank are problematical, but the worst trouble here is that these catfishes at this size are generally marine... Please read here: http://wetwebmedia.com/ariidcats.htm and the related FAQs linked above. Bob Fenner>

Arius after all Nope it is a "catfish" shark, silver tipped shark.  Anyway I took it back to the pet store since another one died and I didn't want to have it on my conscious that I am a fish killer  :)  Thanks anyway <Thank you... will add this common name to our ariid catfish section so the search tool will find it hence. Bob Fenner> 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>

Columbian shark Hi, my name is Chris, <Hello, my name is Bob> I have recently purchase a Columbian shark for my 65 gallon aquarium.  My question is that all day he swims the same pattern around the top of my tank, is this normal for him to do? <Yes, a very active catfish> My sg is 1.007, ph is 8.2, water temp is 79, nitrites, nitrates, and ammonia is 0, and phosphates is 1.0.  Other tank mates are: 5 African cichlids, 2 blood parrots, 1 scat, 1 Mono Argenteus and one tiger barb.  Any help would be appreciated.   <Help with? Your cichlids may not "like" the salt content indefinitely. Please read here: http://www.wetwebmedia.com/ariidcats.htm and the Related FAQs (linked above). Bob Fenner>

Iridescent shark care I was recently given a 39 gallon tank with four fish. I'm not sure what the smaller 2 fish are. They are about 3 inches long and are flat (like an angelfish) and white with very light gray stripes. They also have a "feeler." I haven't been able to id them. <Sound like some sort of gourami... Do take a look here: http://www.wetwebmedia.com/FWSubWebIndex/anabantoids.htm> The former owner told me the other two were Bala sharks but, from looking at pictures I believe that they are older Iridescent sharks. Their heads almost look like hammerheads and they are black with a silver stripe down their sides with a whitish underbelly. They are approx. 7-9 inches long. (although one has no tail fin, I was told another fish attacked it and ate it off).  I have no knowledge of fish but no one else would take them. When we received the tank it had a layer of slime around the inside of the tank, and the filter was filthy and needed immediate replacement. We have cleaned the tank and replaced the filter, but now what do we do to get/keep these fish healthy? <Study... read... I'd suggest having a petfish friend come by first and help you actually identify your livestock to species... Then you can look up their individual care requirements> The former owner gave us stress coat and algae destroyer to add to the water. <I'd leave off with this last product... toxic to all> She was feeding them TetraColor Tropical flakes. Are these the appropriate things to be using? <The food is fine... but you should enlarge the selection> I have read that the sharks prefer more than 2 but these 2 have been together for a while and appear to be fine with just the 2 of them. They also seem to have calmed down from the move. They are peacefully swimming and do not freak out if I approach the tank. However, when we got them one of sharks has a swollen spot on his nose with a red spot in the center of it. So my question is this what do I need to do to provide these fish with a long healthy life? I am a complete novice, but everyone knows that I will take in an abandoned animal. Thanks for any help you can provide me with. Tia <Need to know the actual species... Are these your sharks: http://www.wetwebmedia.com/ariidcats.htm Bob Fenner>

Silver shark cats, WWM I had 3 silver shark cats and eventually 2 died off. The last 1, which I had the longest, was acting weird when the 2 one died and I was wonder if he needs to be in groups or not? The second question I have is do they need to be in salt water? I really need your help. Thanks, Ethan <Read here: http://www.wetwebmedia.com/ariidcats.htm and the files above in blue. Bob Fenner> Arius seemanni please help! Hi!  My name is Rebekah and my husband's name is Chris. <My name is Paul Maud'dib... actually, call me Bob> We got a  10 gallon fish tank over a year ago and our first two fish were Arius seemanni,  or shark catfish.  No one told us they would get so big, we were new at  this!  We just got them a 29 gallon tank.  They were both doing very  well and very active.  They seem like best friends and always swim with  each other.  Tonight we were horrified to look in our tank and see one of  our shark fish dying! <!> We had to leave and when we came back he was dead, absolute stiff as a   board.  The other shark left seems quite sad.  Our question is what  happened?  He was so healthy and active!  We don't want to lose our  other shark.  Let me tell you the symptoms and I hope you can help! My husband heard a loud commotion in our tank and saw the catfish really   freaking out.  He was shooting around the tank at lightening speeds!   Then he started to convulse and swim upside down and his mouth kept opening and  closing and he almost seemed to be gasping for air.  It didn't take him  long to die. He turned really white and the tips of his black fins turned  almost a clear white.  Like I said, he was very stiff when we removed  him.   <Frightening> Where did we go wrong?  We were so sad to loose one of our first fish  we ever bought!  And does the other catfish need a friend to replace the  dead one?   Thank you so much for any help! Bekah and Chris <Some sort of catastrophic injury happened to just the one specimen... Likely it either crashed into part of the decor or rammed up into the hood/top... this does happen... more so in smaller systems than larger. Bob Fenner> Columbian sharks Dear crew I would be very grateful for some advice. I have two Columbian   sharks which are about 5" long, just recently one has started just lying on the   gravel a lot it also has a very large belly. Should I be concerned.    The water is fine & although it is a fresh water tank I  add one teaspoon of salt for every two gallons of water in a 90 gallon  tank.                     happy new year                             James <James, I would add some Epsom Salt (magnesium sulfate), at one teaspoon per five gallons here, in the hope it will alleviate the swelling. I also encourage you to get/use a hydrometer... to measure the specific gravity of the water... I do hope your other livestock can tolerate brackish water... and that you have plans to graduate these catfish to full marine in future. Bob Fenner>

Columbian Shark Question I have 3 Columbian sharks, about 4 inches in a 29 gal. tank.  I've done a lot of reading on forums such as this about them and thought I was doing things well.  I just recently did a water change and changes some of the tank decor to make more room for them.  Now I just noticed one of them has a white, growth looking spot on his tail fin. <Possibly fin and tail rot?>  They usually lay on the ground from time to time but now they do it A LOT.  I'm guessing that that is just because they are getting used to their new surroundings.  But I have no idea about the white, growth looking thing.  Any help would be great.  <I suggest you check out the saltwater FAQs. My best guess is that it might be Lymphocystis  see the picture here to see if maybe that's what it is? http://www.wetwebmedia.com/viraldislymph.htm. If it is there are FAQs to tell you how to handle it or write back and we will work you out a game plan Adam. Good luck, MacL> Thanks Adam Columbian sharks and other large fishes for display 11/9/04 Hi Bob. <Anthony Calfo in his stead> Two questions for ya. First, I was wondering if I could put two Groupers a Lionfish and a Puffer in a 125 gal? <assuming you are looking at the popular varieties (porcupine/dogface puffers, volitans lion, large groupers like panther, etc), then no... this is way too much regardless of filtration. The sheer adult size (or not if they stunt and die prematurely for being crowded) of these fishes makes all in this one tank inappropriate, if even possible. Do look through our archives and on databases like fishbase.org to see and consider the adult sizes of the fishes you with to keep. Now... if you are willing to go for "dwarf" varieties of the above mentioned, there are indeed species of small adult length at maturity that will work here> Second, could I put two Columbian sharks with them? <one would not even fit... these fishes start life as fresh/brackish and may end up at sea (coastal) but get quite large (2 foot range) and yet are no match for the toothy predators - they will get mauled. Above all... this tank is too small for so many large fishes to he kept healthy/humanely> Brandon Zimmerman <do research some more, my friend... there are species to appeal and suit you here to be found. Anthony> Columbian Sharks and Java Ferns Sorry to bother you guys again, but I have two questions I couldn't find on your site. I have two Columbian sharks. They are both still pretty young (about 5 inches). <You'll need about 100 gallons of brackish water to keep these large fish into adulthood.> I've noticed recently that their fins are a little torn, the smaller shark more than the bigger one. I doesn't look at all like it could be fin and tail rot, besides they are both really healthy. They are inseparable and I've never seen them be violent to one another, I was wondering if they could be doing this to themselves since they are the most aggressive fish in the tank. <Possible> (33 gal with the two sharks, pleco, African leaf fish, leopard leaf fish and fire eel) <The eel may be causing a ruckus at night> Don't worry we are eventually moving the sharks to a brackish tank. <Salt will help heal as well as start adjusting them to their adult requirements. Host of reasons for tattered fins. Aggression, very high or low pH, ammonia, very high nitrates etc..> Second question, we have sand as our substrate and have live plants I think they are java ferns. The pet store told us that if the plants are submerged directly into the sand eventually they will start emitting toxic gases that are undetectable and will kill our fish. Because of this I put the plants in little plastic cups filled with gravel and submerged those in the sand. <Will not help> I was just wondering if this was necessary. I couldn't find any info on the net. <Java Fern grows from a "stem" that grows horizontal to the substrate. The fronds then grow up along this stem. If it is buried in *any* substrate it will die and decay. This will result in more ammonia entering your cycle. I know of no other "gas" that decaying Java emits. I planted mine on driftwood. Just cut a sliver, leaving it attached to the wood. Then use this sliver to clip the base of the fern to the wood. That will hold it in place until the roots grab the wood. Don>

Columbian Sharks (Arius seemanni)  9/26/04 Hi There, <Hi, Pufferpunk here> I was just on your website and I found a lot of interesting information about the Columbian Shark.  I do have a question that I did not find an answer to on your site.  I just bought two small (2 inches or so) sharks and I believe they are Columbian sharks.  They are very silver almost metallic grey and very sleek. They have very long whiskers and look identical to a real shark.   <Have you read this? http://www.wetwebmedia.com/ariidcats.htm) Now, my question is: why would they be swimming upside down?  They are not just floating there in they water but actually swimming quickly at the top, upside down!? <Are they upside-down all the time?  Are they gasping for air?  Or do they straighten out after a while & swim normally?> Sorry, I actually have one more question in regards to these sharks... Is it okay to have them in a tank with goldfish?  I know it sounds funny but They are in my 40 gallon with a large (8 inches at least) pond goldfish as well as a 3 inch feeder goldfish and two 2-3 inch fantail goldfish.  They seem to be doing well with them so far but how long will this be okay? <Absolutely not!  GFs are Very messy, high waste-producing cold water fish.  Your "sharks" are actually tropical, brackish water fish that prefer saltwater as adults.  They also grow 14-18" & require a huge tank. You never mix tropical fish with GF.> If you could please answer this I would greatly appreciate it. <I suggest either setting up a separate BW tank for them (expecting to need a very large tank in the future for these fish), or return them.  ~PP> Thank You !!  Ashley

More Ariid Cat/"Columbian Shark" compatibility questions Hi Bob (or other WWM crew member),     I have yet more questions about what I can keep with my Hexanematichthys seemanni. I was reading on WWM that some fish look at cleaner shrimp as a $1.75 snack. Are Hexanematichthys seemanni one of these fish? <Too likely yes. Bob Fenner> Thank You -Joey

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>

Ariid Cat/"Columbian Shark" compatibility questions Hi Bob (or other WWM crew member),     Currently I have two 4-5" Hexanematichthys seemanni In a 30gal long (36x13), But I will soon be getting them a 180gal All-Glass drilled tank that I will use to rise the salinity up to 1.025 (over 18 months) from 1.000. Anyway, I would like to know if they could be kept with a yellow tang and a clown fish+anemone and other inverts. Thank You -Joey <Should work out fine. These are really beautiful catfishes, especially when large, in mixed saltwater settings. Bob Fenner>

Breeding Arius seemanni I have two Arius seemanni (Columbian sharks) in a 55gal tank. Their tankmates include silver tip tetras, zebra and leopard danios, blue German rams, mollies, and angelfish. I know that some of the species are not the best tankmates for various reasons as ph, salinity requirement later in life (the sharks), and predatory reasons. <Yes> However, my sharks are the most peaceful fish in the entire tank! Everyone gets along wonderfully. Now, I had originally started out with just one shark, and then I picked up another a few months later. I know they don't like to be alone. I have another 55gal that I can setup for them. I was wanting to know how to go about attempting to breed my sharks. I have raised various other tropicals, but I really would like to try my hand at this challenge. Any advice would be helpful! Thanks in advance! Sincerely, Theresa <Interesting quest. I don't know/think this ariid catfish has been spawned in captivity (all are wild-collected as far as I know). A few notes: the genus of this fish has been changed: http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=13480&genusname=Hexanematichthys&speciesname=seemanni Adults live in seawater, they are likely mouthbrooders, with the males carrying the eggs, developing young (till their yolk sac is absorbed or perhaps beyond) in his enlarge buccal cavity... females develop "claspers" (protuberances about the ventral area) as a sexual distinguishing feature. Bob Fenner>

Distressed Arius graeffei Hi guys!! <Hi there> I recently added 2 Arius graeffei to my 60"x18"x20" tropical tank society of approx. 25 fish and 14 yabbies. <Yikes... pretty crowded> Unfortunately, these fish won't relax.  There was a third fish at the store when I purchased the 2, and was wondering whether the neurotic behaviour of the purchased 2 was due to potential emotional stress due to separation from their friend/family member. <Not IME... this is just one of the more diurnally active, make that ACTIVE catfishes> The pair haven't settled down after a couple of weeks, and I was wondering whether this was due to the pair being of the same sex, or because of the absent 3rd Arius graeffei. I have constructed roomy rock caves for habitat in the aquarium for their lair, but still no peace.  Their behaviour distresses the ecosystem, and I can't put up with it for much longer!! <Maybe time to trade them in> Please help me with some advice and experienced stories before these two Arius graeffei learn to swim in salt water.. <They may do so... naturally> Kind regards, Aaron and Matty T <Bob Fenner>

Sharks I'm thinking about getting either a Bala shark or a silver-tipped shark.  I'm getting a 55 gallon tank and want to which shark would do better in that size tank,   Can you help me? <<In the future, can you send your emails with the PROPER PUNCTUATION, please. These emails go directly onto our website, and we prefer it to look a bit more professional. Thank you. Also, what is the scientific name of the silver tipped shark? I will assume you mean the Columbian shark, which will grow to about 6-8 inches. Columbian sharks are carnivorous and can be aggressive. Bala sharks prefer to be kept in groups, and are quite pretty and less headache than most freshwater "sharks". A group of Bala sharks will also grow larger. What species of fish are you planning on keeping with your shark? Either way, be prepared to do regular weekly waterchanges. In my opinion, you may be better off with a red-tailed shark or a rainbow shark. Please do not cycle your new tank with a shark, however. -Gwen>>

Arius seemanni Venom (3/7/04) Hi, <Steve Allen today>   I have a aggressive Arius seemanni and I have read that they have anticoagulant venom. My question is, what would happen if I where to be bitten <the venom is actually through the dorsal spines>, would this pose a risk to my health (could I get sick/die), and what should I do if she does bite me? <I found little about this on the internet, suggesting there have been few cases of actual harm. You might w ant to do more research on the web or through a university library. Anticoagulant venoms aren't really likely to kill you, but there could be a lot of localized bleeding. If you got a lot of venom in you, it could possibly cause serious problems. In your position, I'd keep my bare skin out of the tank. Get some puncture-resistant aquarium gloves and keep an eye on him. If something happens, cal your doctor immediately. > Thank You-Joey <Hope this helps.>

Columbian Shark Acting Weird 1/13/04 <Hi, Pufferpunk here> Hello, I am kind of new to this fish stuff but it is fun,   <Welcome to my passion--fishkeeping!  I hope it will become your passion too.> I have a 55 gallon tank and 2 small Columbian sharks, and a couple other small fish in the tank with them, I.e. a red tail shark and a couple of small catfish. <I can already see a problem here.  Columbian Sharks are brackish water fish, that prefer saltwater as adults.>   But my worries are about  one of the Columbian sharks, its belly is huge and it seems to swim in circles and not ever able to gain any sort of equilibrium and maintain normal patterns like the other Columbian,  All other fish are fine and water is of good quality.  It is like the shark is doing back flips and other acrobatic maneuvers...I am just worried and would hate to see it die or suffer.   <Is it possible to quarantine this fish?  I think it might have internal parasites.  It is a common thing with wild-caught fish.  If it's eating, try treating it with Discomed, by Aquatronics.   If you can't separate it, all the fish will have to eat the medicated food.> Thank you so much and I Love your site I have learned a lot.  Dennis Barnard <You're welcome & keep learning--Pufferpunk>

Arius seemanni (shark catfish) with cloudy eye (10/14/03) Hello WetWeb crew!   <Hi! Ananda here today...> I just had a quick question, I have a pretty good sized Arius seemanni, he's maybe 6 or 7 inches and because the tank is a reef tank and he's a little rough, he gets small scratches and scrapes from time to time, he heals up very quickly, but it looks like he may have scratched his eye recently.   <Ack. I'm glad he's in a tank with some salt, but scrapes and injuries are going to be par for the course in a reef tank... these guys are shoalers and need some open space to swim around in.> A day or two ago it started out as a very cloudy, but splotchy looking deal, but now it's uniform throughout his eye but slightly more clear...it is possible he has a disease resulting from the scratch (I ask just because it's changed form slightly) or is it more likely that this is just his healing process?   <Could be a developing infection. You might consider setting up the quarantine tank for him for a bit and medicating with an antibiotic... on the other hand, since it's likely to be difficult to catch him, you might just observe him for a few days and see what progresses. Do keep the water quality pristine, and wear aquatic gloves when you put your hands in the tank to prevent any of the bacteria on your hands/under your fingernails from getting into the tank. Also feed him high-quality foods, perhaps an antibiotic food if you have one that he will eat.> His behavior is completely normal otherwise.   <That's always a good sign.> I appreciate your expertise!  Thank you SO much for your time! Rachael Loose <You're welcome. --Ananda>

Sick Columbian Shark (09/14/03) <Hi! Ananda here today...> I just started a new tank, also my first tank.  The pet store that I bought everything from was no help in setting up the tank.   <Not at all unusual, unfortunately.> After asking many questions all they said was to add salt to the tank.  Well after about two weeks I thought things were settling down after a phosphorus bloom, and learning more about keeping a brackish tank then I ever thought I'd need to know.   <Okay... if you haven't read it yet, hunt up Neale Monks' "Brackish FAQ". A Google search should show several hits; some sites have it in html, others have it in PDF.> The ph is steady at about 7.1-7.2. <Hmmm. Kinda low for brackish, but steady is good. What's your source pH, and what's your s.g.?> The nitrite level is high (5), which I've been told is normal until the nitrogen cycle completes and the biological filtration develops.   <Ack! But too high for your fish. Do a water change ASAP!> Also the natural sea salt was added according to the directions.  However after realizing I might need a specific gravity tester, the tank shows almost freshwater results.  I have been adding salt slowing over the past day to try and bring it up.  I've heard that Columbian sharks like increasing salinity as they get older, so I'm starting fairly low with a 1.006ish specific gravity. (increasing to 1.015 gradually over a year)   <Sounds good. Just use slightly brackish water for top off, and/or use slightly-more-brackish water for water changes.> I can't understand the disappearance of the salt that was mixed in at the start.  Could the filter remove it? <Unlikely. How much salt did you add, or how high a specific gravity did you shoot for at first? Also, what kind of hydrometer are you using? If it's a floating thermometer-hydrometer, it will give you readings that are not accurate for your tank temp -- they're calibrated for 60 degrees F, and you need a chart to convert its reading to get the reading it should be for your tank temp. That's why I'm not fond of those. Well, that, and the fact that they're fragile -- I've broken two of them! For brackish, you either want a SeaTest hydrometer (made by Aquarium Systems) or a refractometer.> Unfortunately the fish were in the tank through my inexperience and changes to ph, salinity, and chlorine removal. They have all held up very well until about three days ago.  The Columbian Shark sits in his favorite corner, but no longer swims, just lays on the bottom.  His dorsal fin is also tucked back and no longer up like usual.  He perks up just fine when it's feeding time, and seems to eat normally.  But then goes back to laying.  There are no noticeable marks, scars or growths.  I'm hoping it's just the changes and that he'll be back to normal soon, but better to be sure.  Thank you very much for your time.  -Dan <It's the nitrite. You could take him out and put him in a quarantine tank, doing daily water changes to keep the ammonia down. Or you could leave him in the main tank and do water changes to keep the nitrites down -- though that would have the unfortunate side effect of lengthening your cycle. I'd go with the quarantine tank -- it doesn't need to be anything fancy; a sturdy plastic container will work. Do check the WWM site for info on quarantining and tank cycling... there are also a few pages about the Columbian sharks. I am very glad you have him in brackish water. And do check out the brackish forum on the WWM chat forums: http://wetwebfotos.com/talk/... --Ananda>

Columbian shark on hunger strike I have learned so much from this website that I am convinced that I should be paying for a subscription!  Anyway, I have a 2-3 year old Columbian Shark that until recently has lived a very happy and healthy life.  About 2-3 weeks ago I moved about an hour and a half away.  I took my shark with me and setup his new tank.  His old tank was a 35 octagon... way too small! I now have him in a 55 gallon tank alone with a nice big pump to give him plenty of current in the water.   <With an ultimate size of 14", a bigger tank will be necessary, eventually.> In the past when things have changed in his tank he refuses to eat for awhile (about 4-10) days.  So after I moved him into his new tank I assumed he wouldn't eat for awhile.   <Have you been testing for ammonia, nitrite, nitrate, and pH?> I was right, but unfortunately 2 to 2 1/2 weeks have gone by and as far I know he hasn't touched his food.  He swims right by it, but doesn't even think twice about eating it.   <What foods have you offered him?> His swimming has become weaker.  I'm afraid I am going to lose him.  Once in awhile he'll be straight up and down trying to almost dig into the gravel... but no food is there.  What should I do?  I figured hunger would make him give in as it always has... but it seems this time he might not recover.   <Although it's never a good idea to rely on live foods constantly, you might want to give 'em a shot this once to stimulate him to feed.  Guppies or other livebearers might make an ideal treat (especially if you've got a friend or someone that breeds them so you know they're healthy), or if he's not too big yet, you could try live brine shrimp.  Though brine shrimp have virtually no nutritive value (think of 'em as popcorn), they do stimulate feeding quite well.  Soaking them in garlic will help, too.  You could also try soaking his dry or frozen foods in garlic.> I was wondering if it was possible that he ate a small rock or something and it's stuck inside of him... making it impossible for him to eat.   <It is possible that he has some sort of blockage.  In that case, you may want to try some cut earthworms to help pass it.> ANY help would be great.  Thanks!  Steve <Best of luck to you and your fish.  -Sabrina>

Arius Seemanni Compatibility <Hello! Ryan with you> Hi Guys. Your site is awesome. <Thanks!> I have a compatibility question. I have been told by a guy at a local tropical fish retailer that I could put a couple of Five-fin sharks (or Columbia Sharks what ever you would choose to call them these days) along with African Cichlids. I have been told and found sites to back this up, that the sharks would be able to protect themselves and do better in pairs than on there own. Is it true that I could put the sharks in with the cichlids? I hope that it is because I think those sharks are very neat to watch. What is your opinion? <I've tried this.  In a 150, I used to keep 10 assorted Africans, a few pictus cats and a pair of Columbia Sharks, Arius Seemanni.  Everything initially was a success.  After a year or two, the pictus cats started getting tormented.  The Columbians were not far behind.  They did defend themselves quite well, but it was stressful enough that I removed them.  Africans are unpredictable- This may work fine for years, or may be WW3 the second you remove them from quarantine and introduce them.  Does the benefit outweigh the risk?  That's the question you'll have to answer.  Good luck! Ryan> Cheers. Mike

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>

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 seemanni Hello! I have just recently found your site and your faq responses are amazing so I thought of you first when I started having problems with my new 55 gal. tank.  <thanks kindly> Right now the tank is cycling, it's about 20 days in and the only fish in the tank are one Black Molly and Two Arius seemanni.  <an interesting mix... not quite compatible either... these "sharks" grow to nearly 24"!> The sharks were not originally intended to be in the tank during cycling but I have had them for a year and a half and they have outgrown their tank horribly and the larger one was actually injuring himself when he got excited so I thought moving him up right away was necessary....I think I may have moved too soon. I have been religiously testing the ammonia levels at the LFS and the woman regularly tells me that the ammonia spike is coming and although my levels aren't toxic just yet I should watch the fish carefully and change 20 - 25% water at least once a week.  <agreed> Ok so the problem. I have followed her directions and in all actuality ammonia doesn't seem to be the problem. But my largest shark is looking bad... his color has drained to a light silvery splotchy color and over the last few days he has slowed down a lot and is having trouble swimming. He sits on the bottom is awkward positions. His breathing is a bit labored but certainly not the worst I've seen. He also looks to be developing a case of hemorrhagic septicemia, but I suspect that it is not his primary problem but rather something that developed from his weakness. Neither of the other two fish are showing any kind of signs of illness. I can only think of one thing that has changed since I set up the tank.  <actually... symptoms like this are common in stunted fish and fishes kept in tanks that are too small... it may be the case here. There is no such thing as a "healthy" stunting of a fish in accordance with their tank size.>  I have been adding salt slowly to bring up the SG, which is now at around 1.011 and this subsequently killed off all of the white cloud I had in the tank  <very good!> and my only choice for feeder fish were guppies :( The larger Arius is really the only one that actively takes live food and it's a possibility that he was the only one who ate them could that be why he is the only one who is affected?  <possibly> I'm going to treat for the septicemia right away, but I don't want to lose this fish, his friend will be lonely so if you have any ideas on what I have done wrong I would appreciate it :( Sincerely, Rachael PS Sorry this is so long! <no worries... and aside from tank size you seem to be well informed and certainly empathetic. Lets treat the fish in a QT tank if possible with a Furan based medication. Best regards, Anthony>


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