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FAQs on the Freshwater Minnows called Sharks Compatibility

Related Articles: Freshwater Minnow SharksBala or Tri-Colored Sharks, Redtail Sharks, Redfin Sharks, Black Sharks,

Related FAQs:  Minnow Sharks 1, Minnow Sharks 2, FW Shark Identification, FW Shark Behavior, FW Shark Selection, FW Shark Systems, FW Shark Feeding, FW Shark Disease, FW Shark Reproduction, Bala or Tri-Colored Sharks, Redtail Sharks, Redfin Sharks, Black Sharks,

Look like sharks to you? Okay.

Greetings.. Thank you for an informative website. Are black ghost knife fish and red tail albino sharks compatible in the same tank? Kind regards, Phillip Chapman.
<They can be; that is, I've seen them kept together. Both need room... this minnow shark can get big (and mean). They are fine in terms of water quality conditions. One needs to make sure the BGK has enough hiding space (a tube is great)... And you need to make sure that both species are getting food. The "sharks" can be very aggressive feeders. A good idea to place food (frozen/defrosted or live... meaty) in two areas at the same time; on the bottom. DO read re both on WWM. Bob Fenner>

Many thanks for the info. It is greatly appreciated.
<Welcome Phillip. BobF>

Sharkminnow Behavior - 10/19/2012
Hi there,
<Hello.  Sabrina with you tonight.>
I've been trying to look for answers all over and haven't been able to find anything.
<Everything you try to find will always be in the last place you look *grin*>
I have 3 sharks in my tank, Redtail shark, Rainbow and Rose line shark.
<All Cyprinids....>
The Rose line seems to like to be on his own swimming around the tank, <This, Puntius denisonii, is actually a schooling fish, and really does best in a group of his own species.  He'd really like five or six pals, if your tank is suitably large (say 55 gallons-ish).>
but the Rainbow shark would chase the Redtail shark around.
<Typical....  Epalzeorhynchos bicolor and E. munense both can be territorial; the Redtail especially.  I wouldn't keep both of these in the same tank, actually.>
They did this for awhile and now they just hang around each other all the time and won't leave the weeds that are in my tank. Is this normal or should I be worried?
<The aggression is normal; hanging out together isn't, though.  Then again, the fish don't read the books!>
Here's a picture if you can make it out.
<Can't, really, not enough to tell anything from it.  Observe the fish closely for any signs of damage or other abnormal behavior.  Test your water for Ammonia, Nitrite, and Nitrate - Ammonia and Nitrite must be ZERO, Nitrate less than 20ppm - and correct with water changes if anything is too high.  Poor water quality can attest for the strange behavior.  Aside from that, if the water is good, just keep a close eye on them.  Honestly, though, I would not keep these two together.  There is a real possibility they'll not tolerate each other.  You might also read more about the shark minnows:  http://wetwebmedia.com/FWSubWebIndex/minnowshks.htm  ,
http://wetwebmedia.com/FWSubWebIndex/redtailsharks.htm  , and
http://wetwebmedia.com/FWSubWebIndex/redfinsharks.htm  should get you started, as well as the links at the top of those pages to other articles and FAQs.  Best wishes, -Sabrina>

... Minnow Sharks, poor grammar, no reading...    7/4/11
hey guys, i just recently baght a bala shark for my tank. but i also have a rainbow shark in there. the rainbow shark is being very territorial and is chasing the bala shark all over and nipping at him. shus i just take the bala shark back or will they eventually be ok with eachother after a few days? thanks, chris.
<The Bala should be moved. You should read: http://wetwebmedia.com/FWSubWebIndex/bala_sharks.htm
and the linked files above. Re all the species you're jamming together here. Bob Fenner>

Rainbow Shark, comp.   7/14/09
Hi, my name is Leigh.
I got a Rainbow Shark (male) a few months ago and lately I've been having some problems with him. I've read through your FAQ's and other sites but couldn't find anything on my problem.
I currently have him with a dwarf flame Gourami, baby angelfish, black skirt tetra,
<Schooling species... Gymnocorymbus ternetzi, very prone to becoming a fin-nipper... not my first choice for keeping with an Angelfish! Groups of 6+, please.>
and a Giant Danio.
<Another schooling species... also groups of 6+... can be a bit boisterous for community tanks with gentle species...>
They are in a 5 gallon tank (I know its small for them, but I am getting a bigger tank around 50 gallons very soon) and when I get the bigger tank, plan to add some clown loaches and possibly a black ghost Knifefish (will the RS and BGK be ok?)
<In theory, yes; but 50 gallons is right at the low end for adult Apteronotus albifrons... these fish are very, very sensitive to poor water conditions; they come from fast-flowing streams and rivers around waterfalls and the like -- need lots of current and oxygen!>
Ever since I've had the shark he's never bothered any of the other fish in an aggressive way, he'd swim with my Gourami and angel and only charge the other fish if they got in his way.
<Pretty normal when young; Epalzeorhynchos frenatum, in common with all Epalzeorhynchos, get steadily more aggressive as they mature. Folks buy 'em when they're young, and assume they'll stay peaceful for life. Wrong!>
But lately he's become very aggressive and has been rubbing the rocks and decorations in the tank. I heard that adding more hiding spots and plants to a tank will calm the aggression of fish, so I did but it only made him worse.
<Adding/moving stuff is hit-and-miss when it comes to reducing aggression; works primarily on the assumption the tank is big enough for everyone, so (re-)moving ornaments alters territorial boundaries. If the tank is so small -- as yours is -- that the territorial fish takes the whole tank as its domain, nothing you do with ornaments will make any difference at all.>
Now he only lets the Gourami and angel hide in them, chasing the other fish out if they go in them, and will go to the other side of the tank to chase the fish, especially my Danio.
<Indeed; Epalzeorhynchos frenatum will be most aggressive towards fish of broadly similar size and shape.>
I thought maybe the rubbing was from 'ich' based on the facts I read about it and dealing with previous cases on the fish I had before, so I've been doing treatments for it but its not helping.
<Ick should be obvious enough; white "salt grains" on the fins and body.>
He's eating normally and my water levels are all normal and I do a 20% water change every week. Do you have any ideas or advice on what this might be?
<Yep; see above.>
I care a lot about this fish and I'm really scared something might be seriously wrong with him. If I lost him I would be devastated since he's done some things I've never seen fish do. By that I mean, if I'm fixing something in the tank he'll swim into my hand and when I pull my hand out of the tank he swims around the top until I put it back in the water. Is that a sign that somethings wrong with him or something else?
<Do read about the requirements of *all* your fish choices *before* you buy them!>
Thanks WWM, I'm really hoping you can help me.
<Cheers, Neale.>

Can Puffers live with Sharks... FW  7/1/08 I just got a new aquarium last week (I caught the water fever must have more aquariums Lol). It is 10 gallons and has been running for the past 3 or 4 days. I have some plastic plants in it and a rock cave. I really like Dwarf Puffer fish and used to have one in a 5 gallon tank. I want to get another one and keep it in my new tank with a red tailed shark. I know that they are both aggressive species so because of that will they tolerate each other. I am not going to put anything else in the tank other than them. If I get them should I get another cave so they can each hide in their own? I have extensively researched both species and still can't decide if they will be compatible. Also will a Dwarf Puffer harm a large snail? Thanks for any reply! Your website is great and I have found a lot of useful information on it regarding fish and turtles. Keep up the good work. -Amanda <Hello Amanda, and thanks for the kind words. The short answer to your question is NO, this combination won't work. The most likely outcome is that the Dwarf Puffers will nip at the Red-tail Black Shark. Adult Red-tail Black Sharks also need MUCH more space than 10 gallons, so unless you (at least) quadruple the size of the aquarium, you couldn't fit one in. Furthermore, Puffers eat snails, and so any snail put in the tank with them will simply be viewed as food. Small snails are eaten whole, big snails a mouthful at a time. The best and most reliable approach is to keep Dwarf Puffers on their own, either singly or in groups, with ~15 litres/4 gallons per Puffer. Hope this clears things up! Neale.>

Black shark... comp.    1/3/08 Hello crew and a happy new year to you all, In one tank I have a pretty small (at the moment) black shark, apart from a few larger Synos he is on his own. <Ah, the Black Shark, Labeo chrysophekadion. Not an aquarium fish in my humble opinion. Maximum size 90 cm/3', maximum weight 7 kg/15.5 pounds... 'nuff said.> I am considering putting him in our main display tank. I have been told that he should be fine with our display inhabitants. <Up to a point these fish are acceptable in communities, but only with other very big, behaviourally robust species and even then only in a GIANT aquarium.> Of course, I'd rather run all this past you before I do anything. His new friends would consist of cherry barbs, Neons, cardinals, Kuhli loaches, ghost shrimps, four eyed tetras, Otos and Corys. <Not in the long term. Even assuming your Black Shark stays VERY undersized, it'll still top 45 cm/18" in length, and has a very territorial personality. These fishes might be ignored as being too small to be of concern to a territorial Labeo, but alternatively they might be chases, nipped, or eaten! Synodontis, Plecs, Hoplosternum, etc. all make more sense as companions. Robust characins such as Silver Dollars could work, too.> Both tanks have almost exactly the same GH / KH / pH / temp. I have 0 ammonia / nitrite and about 1 nitrate with high filtration. The only other point is that he seems to have decimated some of the plants in the tank he is currently in. <Normal; these fish scrape algae from plant leaves, and soft leaves are likely damaged. They will also eat plant leaves that are dying anyway.> Though I have noticed that he leaves some well alone. I suppose I could see what happens, if he only eats one particular plant then that would be ok, I could buy a new plant every now and then. <Indeed. Or else keep with robust things like Crinum, Java fern and Anubias.> Thanks. Kind regards, Steve <Hope this helps, Neale.>

Rainbow Shark, Red-Fin Shark, Compatibility Hi! My name's holly! I recently bought a shark (I'm not sure what type of shark it is) with red fins (ALL the fins are red) and a red body. I thought it was a red fin shark but I'm not to sure...I was wondering if you could tell me what it is.  So when I got it, it did nothing but hide in a little cave of wood that I have in my tank and it wouldn't eat. I got worried so I bought a red-fin shark (I am sure this one IS a red-fid shark) to try to make him come out and eat and maybe be a bit more active. I think it has worked but I'm not to sure. I can see it eating now...should I still be worried? If so what can I do and was adding another red-fin into the tank a good idea?  If it makes any difference I have a community tank and I have: 1 x clown loach 1 x snail 2 x neon tetra 2 x white cloud 2 x big sucker fish 3 x tiger barbs 5 x platies (and the 2 I'm asking about) <Hello Holly. The fish you bought are Epalzeorhynchos frenatum, also known as the Rainbow Shark. This is an aggressive, territorial omnivore from Southeast Asia. Feeds primarily on green algae and tiny invertebrates in the wild, but in captivity does well on algae, algae wafers, small live foods such as brine shrimp, etc. These fish tend to be pretty belligerent towards one another, so adding two specimens isn't a great idea unless you have a really big tank. So if possible, re-home that fish. Yes, they mostly hide in caves, except when out feeding or chasing rivals. Dissimilar fish are generally ignored. For some reason you aren't keeping your schooling fish in schools. Neons, clown loaches, minnows and barbs all should be in groups of at least 6. With clown loaches, you can get by with fewer, but they're shy. By the way, Clown loaches get big: up to 30 cm. "Big sucker fish" can mean anything, but I'm assuming those are either catfish (Pterygoplichthys spp, which grow to 30-60 cm) or "sucking loaches" (Gyrinocheilus aymonieri, to 30 cm, and incredibly nasty and aggressive when mature). Both need giant aquaria (300 liters +). There's plenty more info on "sharks" here -- http://www.wetwebmedia.com/FWSubWebIndex/minnowshks.htm . Cheers, Neale>

Problem (maybe) with my Rainbow Shark... with graphic  3/5/07 <Please re-size and re-send your graphic and msg... no more than a few hundred Kbytes...> Sorry the images were each a few hundred kb but there were multiple ones. I limited it to one. Thank you, Jeremy Roach Hello and thank you so much for your site it has been a wonderful resource!! Let me first give a little history. Here is my current set up. 1-Angelfish 1-Blue Gourami 1-Gold Gourami 1-Flame Gourami 1- Pleco 1-Rainbow Shark 2-Black Ruby Barbs 1-Tiger Barb 1-Green Tiger Barb <Mmmm> I recently got this aquarium from my mother-in-law when she passed away about two months ago.  When I got it we had: 3-Angelfish 1-Rainbowshark 1-Albino Rainbow Shark 1-Pleco 1-Tiger Barb 1-Green Tiger Barb 1-Blue Gourami 1-Gold Gourami 2 Angelfish were killed by the Albino Rainbow Shark.  I since took him to the pet store after reading that you should only have 1 shark.  One Tiger Barb got real fat and sunk to the bottom and died. (Replaced him with another).  So after losing three of my mother-in-laws fish I am a bit jumpy when I see weird things going on. Current issue is that the Rainbow Shark is coming out in the open and lying real still on the bottom of the aquarium.  Usually the Gold Gourami comes down and lies next to him for some strange reason.  After lying there for a few seconds the Tiger Barb and the Green Tiger Barb will come over and start striking at him. <Not atypical behavior> This goes on for a minute or so and then he gets up and goes and hides.  The Gold Gourami does not get attacked but rather he at times chases the barb off.  Interestingly enough the Blue Gourami will come down at times and lie on the other side of the Rainbow Shark and then the barbs will leave him alone.  Is this normal fish behavior or do I need to get rid of the Barbs, or could the Rainbow Shark be sick? <The two barbs are picking on the minnow shark... I would do two things... Get a third Tiger Barb (they will tend to pester each other in a small odd-numbered school... which you would have found had you searched on WWM... And a small decor item for the shark to resort to if it feels harassed.> Thank you so much for your time with this!! <Next time... BobF>

Rainbow Sharks, comp. with dwarf Cichlids sel.    02/17/07 Hi, I have a single rainbow shark living in a 23g, he's (definitely a male) currently living with two dwarf gouramis and a Sailfin Molly, the gouramis and the sailfin molly will be moved out within the next few days, as I finally managed to fix their tank, and set it up and plant it. Anyway I've been trying to find a new tank mate for Kelvin my shark, there are plans in place to move him into either a 4 foot or 3 foot tank when he gets bigger but so far he's all of 5cm long. So I'm after a single fish with personality and was interested in cichlids, but I can't find any conclusive info on the net about any dwarf cichlids that'll live in a 23g and live with a rainbow shark. Any help'd be appreciated. <Mmm... should be of the more "feisty" variety... not the real small Apistogrammas, Nannacaras... Maybe something like the Bolivian Ram...> Oh and the tanks currently got a couple of caves and some plastic plants, I'm going to break up some pots to add more caves and add a few more decorations/caves from the pet store in there too. <Sounds good> Thanks Emma <Do take a look see on the mega-site Fishbase.org using the search term "dwarf cichlid"... and then a cursive look/see on the Net, your Stockists re what they can get from this sub-set. Bob Fenner>

Gouramis and Red Tailed Black Shark   1/19/07 Hi! Pip from Worcester England here! I'm just curious as to why my Red Tailed Black Shark keeps eating the slime off my Blue and Red Dwarf Gouramis? <Nutritive> She doesn't do it all the time, but more often than she used to. Will she stop it? <Unfortunately not likely... and is destructive> The reason I ask that is I have a Male Betta in the same tank and he used to pick on my Gouramis when they were first introduced, nipping their fins and displaying to them, and when I asked at the aquaria shop what I could do about it, the gentleman I spoke to told me not to worry, that it would stop. <Mmm, generally not a problem... as the smaller gouramis are aware of the Betta kin's propensity to do this... will/can avoid it> Sure enough, it did and they've been fine ever since. It's a 36 inch tank, so it's not exactly small and there are plenty of plants and hiding places, and they are all fed a varied diet, though the gouramis and shark do like the algae tablets that I put in, and I notice the slime eating happens more at meal times, especially when there is an algae tablet in there. Could she be trying to get them to leave it alone? <Mmm, not really... as stated the minnow-shark derives nutrition/food from such activity... May also be a bit of an agonistic/territorial display... but whatever the "reasons" this activity damages the Gouramis... if too much... I would at least try adding some "dither-fish"... perhaps some small grouping of barbs, danios... to "draw off" the attention of the RTS here. Bob Fenner> Jewel Cichlid Picking On FW Shark  - 1/18/07 Chuck-I treated the tank for Ich and she seemed to be doing better.  Then I noticed my shark has white patches (do not look like ich) and his fins look like they have been bitten.  After the shark started with these symptoms she is back on the bottom of the tank with clamped fins.  She eats great (runs the other fish away from the food) but she is not active.  I have been doing weekly 25% water changes and all of my levels are fine.  Any additional help would be appreciated. < Now that your jewel cichlid is feeling better it has started to dominate the tank. The truth is that all of the cichlids will pick on this shark and you are probably seeing wounds that are beginning to fungus. I think it is time to remove the shark and treat him with Nitrofuranace before he gets killed.-Chuck>

Red tailed sharks and Goldfish tog. Dear Sir, <<Hello, Lara. Tom with you.>> I read your article about red-tailed sharks online. It was very interesting and informative! <<Wish I could take credit for that one, Lara. Glad you liked it, though.>> I used to have a red-tailed shark in a regular aquarium years ago. <<A very nice fish, to be sure. A little tricky to get appropriate tank mates, however.>> I was wondering if I could keep one in a tank with goldfish? <<The problem here, Lara, is that it might work and it might not. Seems a bit noncommittal, Im sure, but Im from the school that doesnt believe in mixing other species with Goldfish. The safe answer would be, No, but sometimes one can be too conservative. Red-Tails are territorial and can be a bit nasty with small fish. Goldfish dont pose this problem, size-wise. Red-Tails arent fin-nippers, per se, though their behavior can leave you with this impression. You dont mention what type of Goldfish you have (and, I assume you already have these) so I would advise the following. If you have a fancy variety of any sort, dont go with the Shark. These Goldfish would be slow swimmers and, perhaps, the subjects of aggression from the Shark. If you have Commons or Comets, it might be worth a try. These will grow large and Red-Tailed Sharks do better, behavior-wise, with larger fish. A lot of this will depend greatly on the size of your tank, the number of fish in it, the water temperatures (should be mid-70s F. if this is to be successful) and, ultimately, what youre prepared to do if things go South.>> I heard that goldfish need to be in aquariums full of goldfish only. <<By and large, Goldfish have different requirements than other fish do. Theyre adaptable to much colder temperatures than tropical fish are, for one. They require much larger tanks than the majority of hobbyists think they do. For example, I wouldnt place a single Goldfish of any variety into a tank of less than 30 gallons. Theyre messy and place a very sizeable bio-load on a tank which is a big reason for large quarters. Small tanks simply dont provide enough stability where water conditions are concerned. Diet is another factor. Goldfish dont process proteins well. A huge reason for problems like Swim Bladder Disorder and constipation. Red-Tailed Sharks, though scavengers by nature, are omnivorous where Goldfish are largely herbivorous. Something to keep in mind if you go through with your plan.>> Thank you for answering! Lara <<I think Ive given you enough to go on, Lara. If you have anything specific to ask, Ill be here. Best regards. Tom>> Re: Rainbow Sharks   12/17/06 Hello again :) My rainbow is doing fine as usual, and I'm back with another question. I really love this fish and I'd like to have more than one. <Mmmm> I have heard that it is possible to keep more than one in a tank, six being a good number. <... not really a good idea... can be "expeditiously" crowded... for shipping, retail... but almost always will establish a pecking order... with an alpha, sub-alpha individual/s attacking the subordinate individuals... with much tension for all else> I currently have a 20 gallon that I'm cycling. I've been keeping my shark in a 5 gallon with a couple of kuhli loaches, therefore he has not been in the 20 before, and has not established any territorial claims within it. If I were to get more than one rainbow, I'd put them in the 20 at the same time so they all have equal opportunity to establish a territory. <A good technique> Is this a big enough tank? <No...> If I provided adequate hiding spots, would I be able to house 2-3 rainbows in this, or would it be impossible to stop them from fighting? <Very likely the last> Would I have to have 6? (I don't believe I have the room for 6 rainbows, personally) Is this a feasible possibility, or should I not bother due to a guaranteed aggression? <I would seek out other species... barbs, danios... and stick with one minnow shark here... Too much, way too much likelihood of troubles/aggression otherwise> Let me know what I should do :) If I can only keep one per tank, looks like I'll be starting multiple community tanks! Thank you very much, -Michelle <Thank you! Bob Fenner>

Tricolor/Red finned Sharks  11/21/06 Hello there, it's Michelle again! <<Hello, Michelle. Its Tom again, as well.>> I wanted to let you know that the red fin is doing marvelous, and I've gotten myself a pair of weather loaches, and a Kuhli loach. (I hope to get more in a couple of weeks!) <<Sounds great.>> I did have a pictus and of course the bala, but sadly something VERY horrible happened. <<Uh oh>> I was sold a faulty tank- it had a chip under the encasing at the base corner of the tank. Overnight, the tank spread out from under the casing (which was literally impossible to see) and it exploded. The bala and the pictus died. :( I was luckily able to save a few fish. <<Sorry to hear about your Shark and Catfish, Michelle, though Im glad not all were lost.>> Anyway, I wanted to inform that my fish are currently in a 5-gallon Q-tank... they WERE in my 10 gallon Q-tank, but that proved to be a disaster. I'm very ashamed to have them in such a small tank, but it is VERY temporary- I'm cycling a 20 gallon as we speak and they only have to stay in the 5-gallon for a little under two weeks. I make frequent water changes (once every 5 days) and give them extra aeration and filtration. <<Excellent and, theres no need to apologize for anything. I know that you know that this isnt ideal but you dont have a lot of options right now, do you?>> I wanted to know, because I hadn't had the chance to ask before, would clown loaches and red fins interact well? My rainbow has been a great roommate with my loaches- both weather and the Kuhli. Now, I understand that the weather loach prefers cold water, but the temperature is steady at 79, and theyre known to function excellently within a broad range such as 72 to 84 degrees. <<Michelle, Clown Loaches (Botia macracantha) are funny about how they interact with other fish. I say this because they can get along quite well with everyone in the tank or they can turn out to be pretty nasty, particularly with smaller fish. As adults, provided you can get them to that stage, they dont exhibit the almost playful type of behavior that they display as juveniles. Specifically, theyve been known to act in a somewhat aggressive fashion at night attacking other tank mates. As to your specific question, I would say yes, at least early on. There may be some jockeying for territory but a larger tank would help a great deal in that regard. Both grow moderately large so I dont think youll see one or the other being dominant. Provided your Rainbow Shark doesnt mistake the Loach(es) for something theyre not, I think they could make a decent combination.>> Am I making good decisions on tank mates? All of these fish will grow to be large (I intend to get a much bigger tank than the 20 of course, that's my starter tank). Will the rainbow accept them with age? <<As I suggested, I might be apt to have concerns later in their lives more so than early on.>> If not, I'd be more than happy to get him his own tank with a few tiger barbs. I've grown quite fond of him! <<Either way, Michelle, I dont think youd be going wrong.>> Please write back and let me know your thoughts. :) Thank you for your time, -Michelle <<Happy to share it with you. Best of luck. Tom>>

Red-Finned Shark sys. 6/19/2006 Hi there, <<Hello.>> I have been given this address by a friend; I need some advice on keeping certain kinds of fish. Up until now, I have been told by all the pet shop owners/managers that keeping a shark (red finned or red tail) along with my other fish like angels and swords will be just fine, but this shark is actually ripping the tails of all my fish. <<They can be aggressive.>> What to do???? <<Return the shark, or acquire another large system. Lisa.>> Faizel Hoosen

Was Goldfish disease enquiry, now tropical/Betta health, comp.    4/12/06 Hi, <Hello> I'm Karthik. I'd contacted you about that skin flukes/Trichodina problem that my goldfish were suffering from for quite a few months. I lost one Oranda due to dropsy. I treated all the rest with a dose of Potassium Permanganate and then dismantled the entire aquarium, cleaned everything thoroughly and then re-established the aquarium and allowed the empty, re-setup aquarium to stand for a fortnight to allow the beneficial bacterial colonies to develop. I then added my fish back into the tank and now they seem to have got rid of their problem and their behaviour patterns are all normal now. I thank you sincerely for all the assistance you had given me during that time. I'll feel free to contact you in case I need your assistance at any point of time. <Okay> I wanted to know one more thing- I have another aquarium (tropical fish). I have a school of neon tetras, 4 Bala sharks and a rainbow shark. <The Neons will be consumed here> I also have 5 bettas- a  red crowntail, a blue halfmoon tail, a royal blue veiltail, a dark red scissor tail and a Cambodian female betta which I house in separate (obviously), spacious jars. They're all doing extremely well. However, when I add any of these 5 bettas to my tropical tank, they sort of become dull and their fins start tearing in various places after 2-3 days. There are lots of hiding places, and plants like the Cabomba, Amazon sword, etc. and the current due to the filter isn't very strong either. If I put them back into their jars, they become normal again and their fins grow back. I've checked the tank- there are no pH, ammonia, nitrite and nitrate level surges. the temperature is maintained at 24C The water quality is quite good because the other inmates of the tank are doing pretty well and I can assure you that none of these other inmates harm the betta. <Perhaps not overtly> I'm puzzled about this sudden change of behaviour from these bettas. Could you tell me what could be the reason for this? Expecting your reply soon, Thanking you, Karthik <Likely "stress" from being in the presence of the sharks, particularly the Redfin... plus having so much space to swim about in... is wearing on little-used fins. Bob Fenner> Re: Goldfish disease enquiry ... minnow shark, betta comp.    4/12/06 > Hi, <Karthik> Thanks for the information. Now I would like to clarify a few things here. Firstly, both the Bala sharks and the rainbow shark are about 1 to 1 and a half inches long. They're still very young. Are you sure the presence of the rainbow shark affects the behaviour of the betta? <Absolutely. More so though, as you hint, with increasing size> As far as I can see, the rainbow is pretty peaceful and he's happy grazing the leaves of the various plants in the tank and nibbling at everything he can find including the gravel and in fact, that's all he seems to be doing all day. <You will see, learn in time... please see WWM re "Minnow Sharks"... beh., comp... I am in the process of sorting, writing review pieces for principal species...> The bettas and the rainbow shark are supposed to be compatible species anyway. <Not often, no> And how come these bettas don't feel uncomfortable if I leave them alone in a large tank with just the rainbow shark? I've tried that before). <Not long term> You'd mentioned that the neons would become a meal of these sharks in your previous reply to me. I've been careful to choose balas of the appropriate size considering the fact that Neons are existing in my aquarium. They're doing well. I know that neons are from the Amazon and balas are from Thailand but would you recommend this combination? <No... the Balas get too big (35 cm.) are too rambunctious, like very different water quality...> After all, neons reach a maximum size of 2-3 inches <... rarely more than half this> but Balas grow up to 12-13 inches or so I've heard. I've also heard that the rainbow shark gets extremely aggressive as it grows older. Is this true? <Often, yes> I've never had a rainbow shark before. I've had almost all varieties of goldfish over a decade (ever since I was 8, now I'm 19) but I'm trying to expand my knowledge in other tropical fish now- hence the above questions. Expecting your reply soon, Thanking you, Karthik <Welcome. BobF> Goldfish and "shark" uncertainty   3/15/06 Greetings   I am the proud owner of one 4in Lionhead FG, one 2in Fancy G, one celestial eye FG, one 1 1/2 in unknown GF (it has no dorsal fin, humped tail, small pom poms on its face, red and white.  can u tell me the common name?) <Not from the proffered info.> and one 1in black moor.  I also have added a 1 1/2 in rainbow shark, yes this is probably bad.      My question is this:  I have been having terrible issues with bacterial bloom since I have added the celestial eye and rainbow shark. <This minnow is too "mean" to keep with fancy goldfish. Remove it.> It is obvious that this tank has become quite overpopulated (29 gal) <Is too over-populated with just two of the goldfish> and must be the culprit.  All chemical levels are in check.  What can I do to rid the bacterial blooms? <Less fish, feeding, more filtration, circulation, more frequent partial water changes, live plants...> I have tried 2 different types of coagulating agents and this hasn't helped at all. <These "clarifying agents" are not a good idea> No progress here.  Do I need a stronger filter?  It is for a 20-40gal.  I am reluctant to separate these fish because they are currently rather small for now, with the exception of the lionhead, and I don't have the sufficient funds to get another tank right now.  What is my best option?    <To read... on WWM re goldfish systems: http://wetwebmedia.com/FWSubWebIndex/gldfshsystems.htm and the linked files above>   Also, I was fooled into getting my rainbow shark.  Why do all pet store employees give stupid advice? <Mmm, not all... a counter... Why is it that folks are so eager to blindly accept such input? There is no "certifying" agency for such workers...> My fault for relying on them anyway.  So this fish is supposedly very aggressive, yet I  have had him for 2 weeks and he/she swims with the other fish in a friendly manner and causes no problems thus far.  Should I separate him anyway under suspicion?    <Yes. Will eventually become abusive>   I realize now that I really need research more BEFORE I buy fish, if I had, I wouldn't be bothering you, I'm sorry.    <Ahhh!>   Thanks for listening   Christy Bowen <Thank you for writing, sharing. Bob Fenner>

Bala Sharks In a Planted Tank  - 03/12/2006 Hello Again, I wrote about this time last year with questions about filtration for 150 gal aquarium in which I was overwintering my 2 pond fish, a 12 in goldfish and 15 in koi.  I was (and still am) using a Magnum 350 canister, a HOT magnum filled with bio-media, an Emperor 400 and 3 400 gph powerheads pushing the UG filter.  I siphon 50 gal of the water each week using a python gravel vacuum and stir up the gravel so the filters can take out the suspended waste.  When I wrote last year I was complaining about not being able to keep up the amount of waste generated by the fish.  Bob Fenner suggested I clean the filters more often and add a couple of box filters and an air pump to aid in filtering the debris.  I added the filters and a Luft air pump.  When the weather warmed up enough to take the fish outside, I decided they were too big for my 400 gal stock tank so I gave them to friends who had in-ground ponds and I got a couple of smaller goldfish.  Naively, I figured my filtration set-up would be able to handle 2 goldfish.  I brought them inside in Oct. and have been faithfully cleaning the tank and the filters as described above (I swear) and am back with the same problem, I cannot keep up with the waste from the goldfish, they are between 6 to 8 inches.  SO,  I have decided to give up on keeping the goldfish in the aquarium over the winter.  I may give these fish to my pond friends and get some 'mosquito' fish for my stock tank.  Now I'm getting to my question - I have thought for a long time that Bala sharks are very attractive fish but never had a tank I thought was big enough to house them.  Several years ago I had a 75 gal plant tank with lots of tetras and had good luck, and since I have decided to forego the goldfish I am considering a tropical freshwater tank again.  But before I invest in more lighting and live plants, would you tell me whether 3 bala sharks would create the same trouble with waste as the goldfish.  I have been thinking about  having a school of 12 to 15 rasboras, several Siamese algae eaters and 12 - 15 kuhlii loaches with 3 bala sharks.  But I don't want to get it all set up and not be able to keep up with the waste.  I  kept tetras for many years and really do the maintenance I have described.  However, with the goldfish, the pleasure factor is greatly outweighed by the unsightliness of the waste.  Would you be willing to give me feedback about this plan or modifications that would make it feasible?  I'd sure appreciate the help.  Thanks a lot.  Kerry < Bala sharks get big. I have seen them personally up to 18". These of coarse were very old but very well cared for fish. They would be like a bull in a china shop disturbing the planted tank just by their movements. A better choice would be some roseline sharks. They have a similar body shape but a nice red streak to the body. They don't get too big but make a very nice addition to a larger planted tank. they are expensive but the prices are coming down. They would definitely be easier than a goldfish tank.-Chuck> Suddenly aggressive Red-tailed Shark 10/17/05 Hello, <Hi there> I have a 20 gallon tank with 1 male Betta, 2 spotted Corys, 1 red-tailed shark and recently added 3 gold barbs. I had never had any aggression with my red-tailed shark but when I brought home the 3 gold barbs the shark has grown more aggressive. <Yes... happens... and more often with interaction with other cyprinids> He constantly chases the barbs until he himself is exhausted or bored and occasionally gives a brief chase after the Betta and Corys. <Can't likely harm the barbs or Corydoras, but the Betta...> The barbs hang around the bottom of the tank gasping from swimming so much and hide in corners until the shark comes by for another round. Everything I have read says red-tailed sharks are normally compatible with barbs so I'm rather shocked to see him act this way. <As stated... happens.> He has plenty of caves and cave like areas to call home and the barbs are not normally in these areas unless the shark chases them there so I'm not sure why the shark is doing this. He doesn't appear to be actually biting them just chasing them and occasionally when they all get bundled up in a corner he accidentally "or for all I know purposely" rams them. How can I fix this problem and what may have initiated it? Thanks in advance Lynette <Likely "breaking up the environment" a bit more will reduce this apparently agonistic behavior (if the tank itself is large enough... at least 29 gallons let's say). I would provide some floating "bunch" plants... these are listed on WWM, for the barbs to hide in, all to eat at their leisure. Bob Fenner>  <<These fish have been observed living quite comfortably (holding their own) in tanks with very aggressive Neo-tropical cichlids. Marina>>

Mystery Shark And Betta Compatibilities - 09/30/2005 I have a black fin shark <I can only assume you mean one of the fishes here:   http://www.wetwebmedia.com/FWSubWebIndex/minnowshks.htm > and a Betta, can I have both of them in the same tank? <Not knowing precisely what your "shark" is, the short answer is "I don't know".  Find out what the fish is, how large it grows, and its compatibilities, then decide.> I just got my black fin shark what are the best foods to feed it? <Likely prepared flake, pellet, or frozen foods will be fine.> can you e-mail me the answers to XXXX <Done>   Thank you for taking your time to answer my questions. <Please read about these fish on our site.  Much of the information you seek is already archived.  Start here:  http://www.wetwebmedia.com/FWSubWebIndex/betta_splendens.htm .  Wishing you well,  -Sabrina>

Nothing but FW Minnow sharks  9/22/05 My question is I am setting up a 90 gal bowfront and want to keep nothing but freshwater sharks. The only shark I have owned is the redtail. Do you see a problem with housing the redtail, rainbows, albinos, Whitefin blues together as long as I have several of each species and plenty of hiding places?                        Thanks! <These will likely mix, form an uneasy truce with time, growth. Bob Fenner> More than one red tailed shark?  9/1/05 Hello again. Quick question. I have a 108 gallon and have among other fish six "flying foxes". I just purchased a red tailed black shark about 1.5 inches. Settling in ok but have found him to be chasing the foxes now and then. Being similar in shape I understand why. Everything I've heard about this fish is to keep one specimen. This tank is heavily planted and I was wondering if I could or should keep a small school to stop the aggression toward the foxes? Could this work and what would you consider to be an acceptable number in this particular tank?  Leave as is or more sharks?  Your advice is the best out there!!!............Tanks a lot..............Craig P. <It is a very territorial fish, that will be more aggressive as it matures. You can keep the sharks in a small group when they are young, but it will be increasingly difficult as they mature. I would stick with one, unless you want to add 3 more and remove them as they get older and more aggressive. Good Luck, Oliver >

Bala Shark & Oscars <<Greetings, JasonC here...>> First of all I really enjoy your web site, over the past 3 years I have started 3 tanks and your web site has given me the most helpful information. <<Glad we can be of service.>> I have a Bala Shark in a 42 gallon tall tank with an angelfish, in my second 73 gallon tank I have 3 Oscars and 2 Parrot fish, The Bala shark is around 5 inches, Could I move the Bala shark into the tanks with the Oscars? <<You could... but would you want to? Oscars really do their part to tax a filtration system, and by adding anything to that tank you're going to add to the bioload.>> The Oscars are around the same length as the Bala shark and the Parrot fish are smaller. <<It would likely work for a while.>> My second question involves my saltwater tank that has the ecosystem, Caulerpa a UV sterilizes, some bioballs and tribase carbon, my Koran angel has started to develop a slight case of lateral line on one side. I have just started to add vitamins to the their food and fish solution from ecosystems. Has my UV sterilizer killed some needed bacteria? <<Hard to say except that it is defiantly not part of the Ecosystem Aquarium as designed by Leng Sy which in my book is a "designed" system - anything else added to, or altered from the original designs will change the results. I would stick with the "system". Only way to know is to take it out of line. HLLE on the other hand is almost entirely nutrition-related. Your best option here is to make sure the angel gets a good mix of foods including something containing marine sponge [like, but not exclusively, Angel Formula] as that is what these eat most often in the wild. Success against HLLE is less likely to come from a bottle than from a well-balanced, natural diet - no terrestrial vegetables.>> Is my carbon removing some necessary trace mineral? <<I doubt that but you should also not leave the carbon in for extended periods of time - so it doesn't become a detritus trap, and the aforementioned reasons.>> Any thoughts would be appreciated Martin Rischall <<You got 'em. Cheers, J -- >>

Freshwater Shark and Algae Eater I'm looking to get a small shark and an algae eater of some kind. Are there any of these types of fish that can get along? I have a 60 gallon tank and I'm getting ready to add plants and other hiding places. <The shark is going to be a problem to your live plants. Most of the freshwater fish we call sharks are related to carp or catfish and can be destructive to plants. There are many excellent algae eaters available. Take a look at the following: http://www.wetwebmedia.com/PlantedTksSubWebIndex/otosags.htm http://www.wetwebmedia.com/PlantedTksSubWebIndex/saesags.htm http://www.wetwebmedia.com/FWSubWebIndex/loricariids.htm> Thanks, Mike Hodges <You are welcome. -Steven Pro>

Black Shark and Fire Eel - Out of the Frying Pan and Into the Fire! Hello, hope you can help me!   <I will indeed try.> I have been looking for quite awhile and trying to decide what to purchase for my tank or if I need to buy a larger tank if it is needed!  I am wondering if a black shark 2" long and a fire eel 9" long will be good tank mates? <No, black sharks (Epalzeorhynchus bicolor) are said to be very hostile fish.  I've read many sites saying how their red tailed Black Sharks have really hurt some tank mates.  I would think that it would pester a fire eel.> I know that black sharks are aggressive, but are they to aggressive if they grow together! <They will eventually be mean... their nature won't allow them to be nice forever.  No sense putting an eel through that. Here is a quick bit of info on the black sharks.  http://aquarium.wendellarhoads.com/blshark.shtml They seem to list what had happened to their tankmates.> I have heard and red that balas, red tailed sharks, or rainbows and good possible tank mates,  what about black sharks?   <larger rainbows wouldn't bother an eel at all.  The others you run a risk.> Would a lot of hiding places for the eel make a difference or keeping the black shark well fed make a difference? <It would help, but wouldn't take care of the underlying issue that the fish would be mean to the eel.  I suggest that if you want these two fish, you think about having two separate tanks for them.  Then you can enjoy both without worry.  Good luck -Magnus.> Help Needed!!!  Thanks CHO, IA

Discus and Bala sharks Hi Bob: Here Ahmed from Pakistan.  I have some Bala Sharks in my 5 feet long tank. 2 of them are quite big nearly 8 inches and 5 are 4 inches in length. Now I intend to keep small Discus fishes in my aquarium. My question is that can I keep discus with these big Bala Sharks?  Thanks Ahmed < Your Bala sharks will get too big and be too fast for your discus to really feel comfortable and thrive.-Chuck>

FW Sharks and Decaying plants Chuck, Thank you for your quick feedback. Ok, I guess I will have to get another tank for the Cichlids when I know a little more about this incredible hobby. I am enjoying myself tremendously and this is such a stress reliever. I am puzzled by the last comment that was made, "BTW, when you start missing fish, it's the sharks that are doing it." The sharks seem to be the least aggressive of all the fish that are in there. Do they have a hidden temperament or something I should know about? < As your shark grows it will attempt to eat fish that it can swallow. Right now it will not bother any fish it cannot eat. It will get big and eventually the smaller fish will come up missing. Check your sharks out at fishbase.org.> One more question, I put live plants in the aquarium Friday night and I woke up Saturday and fed the fish. Everything was fine and about an hour later the tank was (and still is) extremely cloudy. What could be causing this and does it have anything to do with the plants?  < Maybe. Check the ammonia and the nitrites. They should both be zero. The nitrates should be under 25 ppm.> The cloudiness has a extremely faint greenish tint to it. I checked the PH and it is about a 6.5-6.8. I changed the filter last night in hopes that would solve the problem, but I woke up this morning and it's still cloudy. What do I do? Thank you so much. Sarah <Check the water quality. Do a 30% water change and vacuum the gravel. Don't overfeed. Feed once a day and only enough food so that all of it

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