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FAQs on Pangasiid Cats Mainly the Iridescent/ID "Shark"... Behavior

Related Articles: Pangasiid Catfishes

Related FAQs: Pangasiid Catfishes 1Pangasiid Catfishes 2, & FAQs on: Pangasiid Catfishes Identification, Pangasiid Catfishes Compatibility, Pangasiid Catfishes Stocking/Selection, Pangasiid Catfishes Systems, Pangasiid Catfishes Feeding, Pangasiid Catfishes Disease/Health, Pangasiid Catfishes Reproduction, Related Catfish FAQs:  Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, ReproductionMinnow Sharks 1,


Iridescent shark seizures  6/21/10
Hi There...
I searched your site, couldn't find an answer to my question. My 4 year old iridescent shark has been having seizures the last several days. At first I thought it was the lighting, so I've kept it off, no fix. The only thing I've changed in his environment lately is I started feeding his tank mates a different type of flakes. Can you tell me, is there anything I can do to help him stop having seizures? Should I go back to the old food?
Thanks in advance for your reply...
<It's unlikely to be seizures as such, and more a fright reaction. Unless your aquarium measures thousands of gallons, your aquarium is too small. Seriously. I'm not kidding. Pangasius hypophthalmus ARE NOT suitable for
home aquaria. They get to about 120 cm/4 feet long within a year or two, and they live in groups, and they migrate up and down rivers. Under home aquarium conditions they almost never adapt, and most specimens die
prematurely for one reason or another. At the very least, they end up damaging their eyes by throwing themselves into the glass walls of the tank. Stunting is common, and despite the common myth, doesn't mean the fish has "grown to the size of its tank" but instead means the fish has been chronically stressed for a long time. If yours is less than, say, 75 cm/30 inches, your catfish is stunted, and that means it is probably being kept badly. In short, you need to make sure the tank is very, very large, has an extremely strong filter [8-10 times turnover per hour] and that there are no aggressive tankmates likely to spook them. Do not EVER keep this species singly; it is just as social as a Neon tetra or Tiger barb, and will be just as stressed if kept alone. I honestly wish I could say something more helpful, but I really can't. These fish DON'T adapt to home aquaria, and usually end up damaging themselves precisely in the way you're describing. I doubt the change in food was the trigger, but possibly the tankmates are behaving differently and that's alarmed your catfish. Who knows. Without being told something about the size of the aquarium or its tankmates, I can't really say anything more detailed. I know I'm being super-negative here, but these are fish that shouldn't be in the aquarium trade, and there's really no excuse for shops to stock them or people to
buy them. Every aquarium book ever written has something like "don't buy this fish" written down under the Pangasius catfish name! Cheers, Neale.>

Iridescent Shark, beh., sys.  10/27/09
Hi, was just wondering if you ever heard of a fish slapping its jaws together as if it was eating something but has nothing in its mouth.
<Nope, not seen this. Might be some sort of threat display? Or could be "gulping" water, a sign they aren't getting enough oxygen.>
This is not constant but happens probably once or twice an hour. Since they started doing this, they have been swimming really slow and kind of hovering about an inch or two off the ground. The fish are iridescent sharks,
<Pangasius hypophthalmus, I presume?>
one is about six to seven inches long and the other is about five to six inches long.
<Ah, well, these fish almost never do well in aquaria. You do realise how big they get? Easily 60 cm/24 inches, often 90 cm/36 inches and in the wild more than 120 cm/48 inches. These are food fish, and cannot be kept in home aquaria.>
They are in a 125 gallon tank,
<Too small.>
nitrate between 0 and 20, nitrite is at 0, hardness between 75 and 150, chlorine is 0, alkalinity is 120-180, and ph is about 7.2. temp is 78-79.
The eyes are clear on both of them, I can not see any skin problems to include the fins. The larger of the two damaged his nose when he was introduced to the new tank about a month ago as he was really quick to spook.
<All too common. These are riverine fish used to swimming freely. They almost never adapt properly to home aquaria.>
He is no longer so easy to spook and his nose looks like it healed well with no infection visible to the eye.
<Well that's good to hear.>
The fish seem to eat well only when we are a distance from the tank.
They never used to do that, it really didn't matter if I was standing right in front of it before.
<The bigger they get, the more space they need. In this teeny-tiny tank (by their standards) they're feeling horribly cramped and stressed.>
They also stopped taking food from the surface, they strictly eat from the bottom now. Also was wondering what the max amount of fish you would recommend for this tank as I keep reading how the groups are best around 3 but I'm sure you will tell me the tank is currently to small for 3 even at their current size.
Any opinions would be appreciated
<Time to buy a much bigger tank, or else do what 99.9% of the people who buy these fish end up doing, and that's finding a new home for them at a zoo or public aquarium. These fish simply shouldn't be in the trade, and I can't imagine why anyone would buy them. All the aquarium books state very clearly DO NOT BUY THIS FISH and yet people still do. Pangasius hypophthalmus are food fish, and no more suited to home aquaria than farmed food fish species like Atlantic Salmon, Channel Catfish, Common Carp, or Sea Bass. Cheers, Neale.>

Novice-need help!!!! Learn before you burn... FW induced troubles   3/23/06 Hi I have been reading and I think your website is amazing, probably the best out there!!! Thanks for all your help!!!! You are all great!!! Anyhow, I am so new at this and this is probably the most ridiculous questions but I need some answers: 1- Today I've been seeing one of my ID sharks just sort of laying around the plants (plastic) not being his active self, at one point I thought he was dead cause he was just laying on it not moving, then he rapidly moves across the tank and does the same thing on the other plants? I have also noticed that he looks a bit swollen around his belly, he wasn't like this before, my husband thinks it may be pregnant but it's so tiny, I doubt that!!!?HELP!!!! I hope he is ok!!! what should I do???? <When, where in doubt, a partial water change... What do your water quality test kits show?> 2-I don't know how big my tank is it looked pretty big to me when I bought it was a complete tank with all access: heater, filter, food, etc..) The filter it came with says it's for a 5 to 15 gal tank so I guess that's it???!!!! <There are about 231 cubic inches in a U.S. gallon... calculate> Anyway the question is, I don't know if this tank is big enough -- for now-- <Maybe not... could be these shark catfishes are just suffering from low dissolved oxygen... The real root issue here is highly environmental...> I know I have to upgrade eventually cause my fish will grow big but for now is it ok to have 2 baby iridescent sharks(<2 inches each), 2 tiny upside-down catfishes(<1/2 inch), 1 Pleco (about 2 inches) and 4 tiny neon tetras? <Mis mixed> 3-How often does my tank need water change? some say every wk. others say every 4 wks.? But just recently (3 wks. after getting tank and fishes) I have noticed that the water is starting to cloud up, should I change the water? 4-How often do I feed my fishes? Food says 2-3 times a day, people at the pet store say 1-2x daily and I had someone tell me that he feeds his fishes every other day?????? So I've been feeding 1/daily???? <Posted... on WWM> 5- Should I feed my Pleco peas? Zucchini? will the other fish eat these??? Is that OK? 6- and the most stupid question of all is:::::: When I clean my tank should I take my fish out and put them in another small tank until I'm done cleaning or do I do this with the fish in the tank???? Doing it while they are in there doesn't sound right, but won't taking them out of the tank and then putting them back in stress then out????? Sorry for  all the questions but the people at the pet store don't seem to know what they are talking about, and already I'm attached to my fishes so I want to take very good care of them, plus I'm excited to see them grow!!! Thank you for your time and for answering all these crazy questions!!!! <These issues are detailed on our site. Read, learn to use the indices, search tool... Much for you to be aware of related to these issues. Bob Fenner>

i.d. Shark   3/2/06 Hi there I just emailed you but I just thought of another question sorry about that! My i.d. shark does not seem to like to come out during the day but when I shut the light off he comes out. It seems to me like he is just playing shy but we have had him for3-4 months now. Why is he doing this? We have taken him out a couple times and changed the tank around to see if that would help because we were told that it could be a territorial thing but he still just lies on the bottom of the tank and if he sees us looking in the tank then he hides behind something. Can you explain to me what Ich looks like please and what I can do if I get it in my tank? I have 2 fish I believe are pregnant and I do not want to take any chances with Ich and just want to have a heads up about it. Thank you very much I love your site it is so helpful. I have spend the last 3-4 months looking for good information but I have not yet been able to find anything. A lot of websites contradict themselves. Amy <Please see WWM (use the Google search tool on the site) and Fishbase.org re this fish... You will soon know its ultimate size and water quality requirements make it incompatible here. Bob Fenner> << http://fishbase.sinica.edu.tw/Summary/SpeciesSummary.php?id=14154>>... yes... five feet long... needs a six foot long tank, others of its own kind...

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