Plausible ID Sharks, stkg./sel.    8/3/11
Recently we purchased a tank that came with 4 sharks, the species of which the owner could not remember. After a lot of research we believe we have determined they are ID sharks, and with further research, we are not very thrilled at this discovery.
<I'll bet. I wouldn't be either>
Our tank is 75 gallons and about 4 feet wide; clearly not big enough for 4 ID sharks.
So I have two questions really.
1) These sharks are 2 years old and are about 7 inches long. Given that most sources suggest they get much bigger and also grow rapidly (meaning I would think 2 years would be long enough for them to have grown more) , is it possible they are simply a similar breed?
<Mmm... a similar species perhaps... See Fishbase.org re the genus: Pangasius
some get much larger...>
I doubt it, as they look identical to some of the pictures people have posted on this and other sites, fit the Wikipedia description to a "T" and behave exactly as people have described in previous questions.
<Pangasius hypophthalmus is by far the most trafficked species in the family>
But because of the size discrepancy, I thought I should at least entertain the possibility. It's much more likely that the tank size has stunted their growth, but then I wonder how two years wasn't enough time for the rate growth of their internal organs to overwhelm the rate of growth of their external bodies. Or more bluntly, why they haven't died yet.
<At the stated length, these might not yet be "that" damaged by crowding>
2) You tell people to get rid of these sharks, quite frequently in fact.
How would you suggest going about doing that?
<Mmm, Craig's List and the local like, trying to find an individual or service company with a large-enough system, use... Perhaps, though less likely, contacting a near-enough public aquarium>
Many sources suggest donating them or selling them back, but the fact that these sharks seems to be the scourge of the aquarium world leads me to believe that this is easier said than done.
<Well-stated>
I could not in good faith, give my fish away to an unsuspecting elementary school that could not house them properly and it seems that aquariums get quite enough of people trying to get rid of these very same sharks. Presumably it is the same thing with pet stores.
Thank you for your help
Jeanette
PS if you would like pictures, I can do my best, but so far my efforts have only managed to capture blurs of fish as they rocket around the tank.
<Heeeee! Thank you for sharing. Bob Fenner>
Re: Plausible ID Sharks   8/3/11
Thank you for the link, that will certainly prove helpful once I find the time to wade through the list of related species.
In the meantime, we will assume these are in fact Pangasius hypophthalmus.
Getting a larger tank to house them is not an option, this tank is meant to be a beautiful (but well-cared for) hobby, not a lifestyle. Is there anyone who would even want these fish? Our local aquarium is the Baltimore National Aquarium, if I had to hazard a guess, I would say they are probably not too interested.
<I would contact the folks there and inquire just the same. They may know of others who might be able/interested. BobF>

Iridescent shark 7/21/07 hello, I have two iridescent sharks in my aquarium I had to empty my tank and clean it out. I got it second hand and I guess I should have taken the rocks out and replaced them first. I transferred the fish into a temporary tank, well to tell the truth it was an ice cream pail. but when I returned them to the aquarium they were both very red (as I am sure you know these are silvery and black normally). one of them instantly began to swim and carry on like normal and he got his color back in no time at all ,however the second one just stays laying at the bottom and swims around lazily along the floor he has not turned back to his normal color. did I shock them in the move and will he pull out of this? all the other fish in the aquarium have also resumed their own happy fishy lives. <Greetings. I hope that you work at a public aquarium or have a gigantic aquarium in your basement. Iridescent sharks -- Pangasius hypophthalmus -- are possibly the worst aquarium fish in the trade. In fact, practically all fishkeeping writers and experts consider them totally unsuitable for home aquaria. Here's why: maximum size is 1.3 m (over 4 feet). They are schooling fish. They grow extremely fast. They are extremely nervous and often damage themselves by swimming into things when alarmed. You have discovered this. As they mature, they will become more and more nervous as they feel confined. Yes, their colours will return once they recover from their state of alarm, but once frightened again, you'll have to go through the whole process again. Almost no useful information is provided by retailers when these fish are sold. In terms of basic care they are herbivores, and need lots of green foods. They live in huge river systems, and so expect a strong water current and lots of swimming space. Minimum aquarium size is something like 4000 litres/1000 gallons. Remember, these things can get to the size of small dolphins! To be fair, most specimens seem to stop growing around the 60 cm/2 foot mark, but even then, given their activity level and the fact they need to be in a school of 6 or more specimens, you still need a simply ginormous aquarium to keep them properly. It is really a food fish and widely farmed, and unfortunately a few specimens seem to find their way into the aquarium trade. Any retailer stocking these fish and not telling you what they turn into is being grossly irresponsible, in my opinion. On the plus side, they're not fussy about water chemistry and are harmless towards fish too big to eat. They also taste very good. Cheers, Neale>

New Shark Dear Mr. Fenner, I purchased a new shark a day ago at the local pet store. They called it a "blue white fin shark" since it has horizontal blue and white stripes on it. I can't seem to find any information on this shark anywhere and I need to know how to care for it.  <please resist buying an animal before you know its needs, my friend... at any rate, by the description it is still unclear what species you have. Please browse our archives from the index page at WetWebMedia.com. AS just a guess... does the body shape of your fish resemble the iridescent shark here: http://kingsoftheaquarium.tripod.com/iridescentshark.htm> It doesn't seem to eat anything right now. At this time I am not sure as to how large this shark grows, if it will get along with the other fish, or any general information on it.  <if it is the above species... it is peaceful but grows enormous (18+")> The shark, which is about 2" in length, is in a 10 gallon fish tank with 2 zebra Danios (I'm not positive about the name, but they are zebra fish), 1 cat fish, 2 Gouramis, 1 painted glass fish, 2 Neon Orange Mickey Mouse Platies, 2 tetras (whose type of tetra is unknown). The pet store employees weren't very helpful, as they didn't know much about the shark. Please help me A.S.A.P. by sending me information about the shark (how to care for it, if it gets along with other fish, and how large it grows).  This will be greatly appreciated. Thanks for your time and help, <best regards, Anthony>
Re: New Shark Dear Mr. Fenner, <The previous reply was from Anthony Calfo. Steven Pro here with the follow up.> Thanks for your help before. I think I have the iridescent shark you mentioned. Do you have any advice as to what to do now? <My best advice is to return the fish.> We didn't know any information on it because the store gave the improper name for the shark and they never provided us with any information about it. <And yet you still elected to purchase it anyway knowing nothing about its adult size or captive care requirements. Do not get me wrong. I understand how easy it is to just get whatever your store recommends, but these are live animals. And with their purchase, we assume responsibility for their lives. The live or die dependent completely on us. It is therefore our duty to fully understand what our pets need and to sincerely determine whether we can meet their requirements before we buy them. I will climb down off of my soap box now.> We only have a 10 gallon with 10 other tropical fish (as mentioned in the previous message). <From your previous listing, I would stick with peaceful Barbs (such as the Rosy or Cherry Barbs) and different types of Tetras.> Thanks again, Brittany Simmons <You are welcome. -Steven Pro>

The Great White Shark of FW Aquariums  2/1/06 Hi, <Hi, Pufferpunk here> My son received a ID Shark for Christmas in a 5 gallon tank. As you do, we added a few things: stones, plastic water plants and a kissing fish along with a heater and small charcoal filter. <Woah!  That kissing Gourami will grow as large as a foot & your iridescent shark, 4 feet!  Here's a pic of an adult: http://www.planetcatfish.com/catelog/pangasii/pangasiu/172_12.PHP  There aren't too many fish that live out their life in a 5g tank, other than a Betta or a few tetras.>   It is now a month later and today we have notice that the ID shark is acting rather frantic, with pauses of lying on his side. The other fish is chasing him, which is new as of today. <Kissing Gouramis can get quite aggressive.> The food and the water purifier are all recommended by the pet shop. The only thing we can think of is that maybe the tank has become too small for the two fish. <Correct in your assumption.> He isn't that large (2 inches) but we were in a pet shop this past weekend looking to add another fish when we were informed that ID sharks can grow quite large (8 inches) and that our tank would be too small for a third fish. <Correct again, except for the 8" part.> Do you think it could be the size of the tank at this point? <Exactly!  I'd return them both & buy fish more suitable for such a tiny tank.  Maybe a beautiful Betta or 3 small tetras.  ~PP> Janice P.S. The food is Nutrafin max for tropical fish.

The Pangasius sutchii - Next time, Please Refer to the Corrections FIRST link! Dear ????, <Mike G with you this afternoon> ill introduce myself: I'm Bennie Tuil from Holland and found your email on the internet. id like to know if you really got the Pangasius sutchii. <I don't quite follow what you are asking. I myself do not have any Pangasius as they grow too large for the aquaria I maintain.> because I do have the Pangasius sutchii but id like some info. about them. <Pangasius sutchii are fish that are, for the most part, unsuitable for home aquaria. They attain very large sizes, and are actually a food fish in their native land. Please refer to the following links for more information on this fish: http://www.wetwebmedia.com/FWSubWebIndex/pangasiids.htm http://www.wetwebmedia.com/FWSubWebIndex/pangasiidcatfaqs.htm Best of luck, Mike G> Holland