My Columbian shark refuses to eat   9/24/11
Hey there guys,
I've been reading your website quite a bit for the past few months to learn more about my fish, and it's really helped me a lot. However, I haven't found a satisfying answer to a serious problem that I hope you can help me resolve. Three weeks ago, My house lost power during Irene for about a day and a half. My tank is a 75 gallon brackish setup (s.g. 1.008 at the moment, increasing it by about 0.001 each week with water changes) with two Columbian Shark catfish; one is 8 inches and the other is about 4.
<They are notably gregarious, and it's not impossible for the fact there's just two of them to be causing some degree of stress.>
Ever since we got our power back, my bigger catfish has absolutely refused to eat, and his behavior has changed (though the smaller one seems completely fine). Rather than swimming peacefully with his tankmate, he thrashes around the tank frantically in tiny circles and is easily spooked. He also keeps opening his mouth really widely, as if he is yawning.
<Does he swim into the outflow from the filter? This often happens, and may indicate a migratory instinct. Big tanks, strong filters, and higher salinities all seem to help. Adults are more or less marine fish.>
Also, his anus appears to be slightly inflamed and reddish,
<Odd.>
and he is beginning to look emaciated.
<Doesn't sound good.>
I have done everything I can possibly conceive to help persuade him to eat.
I did a 50% water change that week on top of my usual weekly 1/3 water change and tested the water, but I haven't detected any ammonia or nitrite.
Nitrate is about 40 last I checked, but that was before I did a 1/3 water change a few days ago. I gave him frozen bloodworms and squid, but he refused that too.
<Try bits of white fish fillet and prawns, these are favourites. And just before a water change, try small bits of oily fish like salmon and mackerel, as these seem very popular but they are messy.>
I put activated carbon back in my filters this week after I read about the possibility of bad water being fed into the tank from the filters after the outage. So far, no change. Is it possible there is a toxin still in the water that is bothering him?
<Unlikely.>
Or maybe he has an infection or parasite?
<If you haven't added any new fish, then it's unlikely. I assume you don't use feeder fish, because they're an obvious source of trouble and should never be used. Do try raising the salinity substantially. As they approach adult size, these Ariids would swim pretty much to the sea, inhabiting estuaries and coastal waters, and adults never seem happy in anything less than SG 1.010 at 25 C. Next up, you might consider an Epsom salt treatment for constipation, 1 tablespoon per 5 gallons, ideally alongside a dewormer.>
If so, what medicine should I give him? Could he have swallowed some gravel and it's lodged in his GI tract?
<Conceivable, but unlikely.>
If so, is there anything I can do to get it out or help him pass it (like a laxative)?
<Epsom salt plus unshelled crustaceans such as whole krill and whole brine shrimp; these strict carnivores are unlikely to take peas, but it's worth a shot. Do bear in mind the whole Thiaminase issue with carnivores, and it's crucial their diet is balanced and doesn't include too many Thiaminase-rich foods.
http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm
>
I'm running out of ideas and I'm desperate to help him however I can.
Thanks.
<Have asked Bob for advice here; he may have seen similar with other marine predators. You may also want to contact the folks at PlanetCatfish; again, someone there may have encountered this with predatory cats such as Pimelodids. Cheers, Neale.>

Re: Shark Catfish, fdg. 1/23/08 Hi Neale, <Neervana,> I read one of your links that you gave me, the planet catfish website and it says that a shark catfish will gorge itself until it has a swollen belly the size of a marble, well one of my shark catfish looks like this, and the other has a slightly bigger belly (it was bigger when I fed them but its gone down a bit) so does this mean that I should not feed them tomorrow? <Just because they *will* gorge themselves doesn't mean they *should*. Much better to feed a small amount each day. Just enough to keep the body full but not swollen.> Because Catfish Planet also says that the fish can happily live with the food they have eaten up to a week and that you have to be careful about how you feed them. <Correct; this is actually normal for most predatory fish. In the wild Pimelodus will capture a small fish, and then use the energy they obtain from it to last them a few days. Sometimes they will eat lots of fish, and then other times of the year hardly any food for weeks at a time. While this allows them to survive in a variable habitat, it isn't essential in the aquarium.> So does this mean I should not be feeding them tomorrow? <I prefer small amounts of food across the week rather than two or three big meals spaced out across the week. The key problem is that if you put a lot of food in the tank at once, then there is a much higher risk of a spike in ammonia and nitrite. Catfish sometimes regurgitate lumps of food if they eat too much, and that adds ammonia to the system too. There's absolutely no advantage to allowing fish to gorge and then starve for a few days. Much safer to give small amounts of food on a regular basis. The filter can handle a low level of food much more easily without any ammonia spike. Just as with any other fish, really.> Thanks, Neervana. <Cheers, Neale.>

Hello Neale, <Neervana,> Just a quick question. Can I feed my Shark Catfish Tetra tropical flakes? - 1/24/08 <You can certainly try. Whether they'll eat them is another matter. But I'd expect them to eat them, at least while the flakes are fresh. I find flake food more than a couple months old gets ignored by fussy fish.> Just trying to keep their diet varied. What other frozen foods can I feed them apart from bloodworms? <I'd try chopped mussel, krill, and Mysis first. Frozen seafood mix from the supermarket or Asian food stores is usually better value though. I get the bags with mixed mussels, prawns, and squid in them, which from Waitrose cost about £3.50 for a big bag. Lasts a long time (unless I at the seafood first!) and because it's a mix, there's always variety. Chop the seafood into small pieces first, and then defrost in a little aquarium water (don't want chlorine smell on the food from tap water!). The add the bits of food either directly or using forceps if you have fish that are tame.> Thanks, Neervana. Ps: My fish recognise me now, when I come into the room they swim up to the side of the glass and start doing a weird dance for food! Doesn't work though !!! <Good stuff! Fish *do* learn, and they *can* become tame. It's a good sign when this happens, because you can quickly learn to spot when the fish are happy and when they're sad. Experienced fishkeepers often say they don't need test kits because they can spot when something is wrong in the tank by how the fish are behaving. While I'd never say throw out your test kits, there's certainly an element of truth to this. Cheers, Neale.>

Advice please. Re: Shark catfish, beh.  - 1/24/08 Hi Neale, (or if it's someone else) <It is indeed me.> I just wanted to say that my two shark catfish are doing very well now, they have calmed down a lot and are swimming peacefully but are trying to hide in a place where they can't be seen! The bulges in their stomachs have now disappeared (due to feeding them bloodworms yesterday) and I'm going to feed them tonight with a Tetra pellet each. I will take your advice on feeding them sparingly, with food each day other than big meals. <Cool.> When do you think I should do a water change? <Same as ever: once a week, 25-50%.> Because I just got them yesterday and I bought a tank for them so they could be alone, I don't know when I should change the water. I'm going to try and buy a vacuum gravel tomorrow with a water tester. The tank is fully cycled, but because they are new fish I don't know when I should start doing water changes. I know it should be once a week, but if I change it this Sunday is that too soon? They are very active and seem to be very healthy, breathing normally, have bright and have not lost any colour at all. They aren't stressed but sometimes they start swimming around crazily (which I take is normal from your previous answer to my email). <Don't worry about it. They're riverine fish, and swimming rapidly is what they do. Sometimes people turn the lights off just before doing water changes, so that the fish calm down a bit. Worth a shot I suppose, but since they're catfish I doubt they care whether the lights are on or not. Just don't chase the fish about with the hose pipe! Be gentle, and pour the new water in gently too.> Would appreciate it if you could advise me when to make the first water change. Is there anything else I should be doing? <Sounds like you have everything covered. Good luck!> Thanks, Neervana. <Cheers, Neale.>

Shark Catfish... beh., fdg.   Hello, <Ave!> I just bought two shark catfish, they are completely silvery with lots of black spots. <Sounds like these are in fact the Pictus Catfish -- Pimelodus pictus -- a South American freshwater catfish. Check the pictures here: http://www.planetcatfish.com/catelog/species.php?species_id=276 The usual "Shark Catfish" of the hobby is Sciades seemanni, an estuarine species.> I put them in my tank and fed them some bloodworms, about half a cube. Then when I came to look at the tank I noticed that both of them had large stomachs, it seemed like it was bulging out. Is this normal? <Sounds like they just ate a lot. So long as the bulge goes away in a couple of hours, don't worry about it.> I have read so many articles on bladder problems in fishes that I am getting worried in case something like that has happened to them. The lady in the LFS did say they eat bloodworms, so I that's why I fed it to them. What have I done wrong? <Likely nothing wrong.> Also, could you please tell me how to care for them properly, as I am not too sure if I have got my facts right. <Do read here: http://www.wetwebmedia.com/FWSubWebIndex/pimelodids.htm Basically easy to keep, but hyperactive and predatory, as well as fairly big, so bear that in mind.> I bought some bloodworms, tropical flakes (tetra) and some catfish pellets (tetra) and some other protein pellets as well which are JMC I think. In a plastic container, transparent with an orange top. <All sounds fine. They eat pretty much anything (including small tankmates!).> Thanks a lot for any help you could give me. Neervana. <Cheers, Neale.>
Re: Shark Catfish 1/23/08 Hi Neale, <Neervana,> Thanks so much for your quick reply, was getting a bit panicky! So if they are swimming around really fast it doesn't matter? <Depends how you define "does it matter". Obviously these are active, river fish that need lots of space. In a small tank they will never do well, and will likely jump out or simply become nervous or sluggish. For Pimelodus pictus, the tank should be at least 1 m long from side to side, and should also have lots of water current, so the fish can enjoy swimming into the stream.> I forgot to mention that, they are going crazy, they are swimming REALLY fast and going crazy in the tank. <Typical for the species.> Do I need to add some stress zyme to calm them down a bit? <No. [a] That isn't what StressZyme does and [b] you can't calm them down -- they are river catfish and WANT to swim about.> Also if I have fed them bloodworms today, should I feel them those pellets tomorrow? <Always a good idea to rotate food items. You wouldn't eat the same thing every single day, would you? Mixing things up ensures the fish don't get bored and get a nice balance of nutrients.> Thanks, Neervana. <Cheers, Neale.>

Columbian Shark Diet   1/30/07 Hi again. <Hello.> You guys are starting to become a habit. <Addiction may be a more appropriate description at times.> All for the good of properly taking care of my pets I guess :-). <Pleased to hear it.>   I have two Columbian sharks about 4 inches big.  I have been feeding them flakes, blood worms and guppies ever since I got them.  I want to cut out the blood worms from their diet because I read that I should not feed them meaty foods too often. <If you are referring to those in the family Ariidae they are omnivorous and as they age prefer more protein in their diet...in fact in adult-hood they can become quite predatory. Do search WWM re: for proper care as these animals require quite specific care and grow to a substantial size.>   I bought some sinking shrimp pellets and now they won't eat them.  They are too use to floating foods and do not look on the bottom of the tank for any food.  The pellets just sit there on the bottom of the tank while the fish swim over them for hours.  Can you please tell me how to get them use to the pellets?   <They may simply not like them, perhaps try mixing them with other foods. You should feed a varied diet anyway.> Is it possible that the gravel and the pellets look too similar and that is why they cannot see them? <Not likely...> Thank you for you help and time.   <Anytime, Adam_J.>
Re: Columbian Shark Diet   1/30/07 Can I try starving them into eating the shrimp pellets? <Ummm....I guess you "could"....I wouldn't....>

 Columbian Catfish diet   12/3/06 Hey there, <<Hey back. Tom here with you.>> I'm planning on getting two Columbian catfish and I was wondering what are some good foods to feed a Columbian catfish? <<Well, as Catfish are primarily scavengers, sinking pellets such as shrimp or catfish pellets are a good choice early on. A high quality flake food will be readily accepted as will meaty foods such as Mysis shrimp, brine shrimp, prawns, bloodworms, beef heart, plankton and krill. Note that the meaty foods I've suggested should be fed sparingly and not made into regular diet foods but rather treats for varieties sake. Personally, Id suggest you resist the urge to provide feeder fish such as Guppies and, particularly, Goldfish. The nutritional value of these is next to nil and can easily transmit diseases to your pets. I would also add that the practice of using feeders will bring out the predatory instincts of these Sharks to the extent that your chances of keeping ANY other fish in the tank with them will be non-existent. One final note, please research the care needed for these fish! They have very, very specific requirements where water conditions are involved being a brackish species as juveniles and requiring full marine conditions as adults. Additionally, given their potential size as adults (upward of 20 inches and possibly longer), you will need a very large tank for these fish. While there are some large fish that don't require a lot of swimming room (the common Plecostomus, for instance), this species is not one of them. While I wouldn't recommend these fish to the average hobbyist, I do wish you good luck and hope you enjoy your pets for many years to come. Tom>>

Ariid Not Eating; Environmental? - 05/17/2006 Hello WWM Crew! <Hi!> Thanks for your wonderful website. <Thank you for enjoying it.> I have an 11 inch long Colombian cat shark. Lately he had been eating voraciously. About 10 or more tablets per day. <Wow.> I have been feeding him by hand. He also has been wading in place at the top of the tank with his head sticking out of the water as if he was gasping for air. Yesterday I did a routine partial water change and he appears to be getting worse. His mouth is completely open all the time (as if his jaws were stuck), his head partially sticking out of the water, and he has stopped eating. <Thus far, it sounds like an environmental issue.> Other fish in the tank: 3  Monos. The hydrometer reading is: 1008; ph 7.2; alkalinity moderate; nitrate 40. <Nitrate is far too high, should be half this at most.  What about ammonia and nitrite?  These MUST be ZERO.  Try doing more water changes first and foremost, and see if he begins to improve.> I hope you can help me.   <I hope so too!> Many thanks,  -AP <Wishing you well,  -Sabrina>

Columbian Shark on Hunger Strike  2/1/06 Hi there guys, <Hi, Pufferpunk here> My Columbian shark stopped eating approx. 2 weeks ago.  He's over 1yr old and I don't want him to die. We have 2 other younger ones in with him & they seem to get along fine.  They are healthy and eating.  The older shark was not eating before we got the smaller ones.   <I don't understand why you would be adding more fish, when the one you have isn't well, adding stress the unwell fish.> All the water tests we did turned out fine.   <Fine means nothing to me.  Please post ammonia, nitrIte, nitrAte, pH & SG.> Our water is half way brackish.   <What does "half way brackish mean?  Specific gravity please.  Are you using marine salt & measuring with a hydrometer? Do you have any ideas? <Knowing tank size, water change schedule & any other tank mates would help too.  Get back to me & I'll see if I can help your fish.  When you write back, please use the proper capitalization & punctuation.  ~PP> Angie Fredericks

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>

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 Thank you!!! I've found my fish! I love these fish but I can't get them to eat anything. They seem very languid and not energetic like they were when I got them. I was wondering what I can feed them or do for them to get them to pep up? <Mmm, almost always these brackish to marine fish are very eager eaters... Likely what you need to "feed" them is salt... to their system. Please read: http://www.wetwebmedia.com/ariidcats.htm and the brackish Subweb on WWM linked therein> They're only 1-2" long but they'll be getting a huge brackish tank soon (now that I know that's what they need). I'm just worried about their survival in the next couple of days because they've gotten quite a bit slimmer in the two days that I've had them. Any help would be greatly appreciated. Thanks! Logan <Oh! Sounds like you know re their chemical environment needs... do check pH, try some meaty, sinking food choices... they'll catch on soon. Bob Fenner>