VI. Some Fish That You May Not Want part 2:

Iridescent Shark Catfish

Pangasianodon hypophthalmus, the Iridescent Shark Catfish, is a large omnivorous migratory catfish from the Mekong Basin. The fish is widely aquacultured in its native areas. It has a listed maximum standard length of 130.0 cm or ~51.2 in; not exactly a small fish. An even more interesting bit of information is that at full size its body weight would be expected to be 44.0 kg or ~97 pounds. To further complicate the fish’s would-be keeper’s problems, this is another schooling fish, with a suggested minimum group of five individuals. Alone or in too small a group, the fish will be much more nervous and skittish. Most of the traded-in catfish of this species which I have seen showed moderate to severe injuries of the head and eyes from slamming into the glass or tank equipment. Now let’s see – the needed tank size for a group of five over four-foot long fish which weigh close to a hundred pounds each, are very fast swimmers, and extremely easily spooked fish would be what? Something larger than home swimming pools, but perhaps a bit less than a competition sized Olympic swimming pool? Try to imagine the water and power bills.

Get real folks. This fish is captured as relatively small fry for aquaculture when smallish, and some of those fry are shipped out for the unsuspecting hobby fish keeper to consider buying. There is little or no possibility of the average hobbyist successfully keeping this fish properly. Realistically there is no reason why even the mega-millionaire would want to do so. The fact that these fish are even offered for sale is a reflection of the store’s greater interest in their bottom line than in the welfare of the fish. The attitude that permits them to sell such fish to the unsuspecting hobbyists is one of the worse condemnations of those operating pet stores. It really is comparable to selling horses as house or apartment pets. It just cannot be well done.

If you see this fish for sale, pass them up. Attempting to keep these fish in the home would be a long and massively expensive and highly frustrating way of emptying your bank account and piling frustration on your own head. Have you

ever seen or heard of a captive tropical of the scale of these fish? If you are out-spoken, feel free to let the sales staff know how you feel about the hobby sale of such fish. The odds are they do not know, but there is little they can do about it anyway. Telling the owner might be better, but in my experience is equally likely to be futile. I no longer try to be Don Quixote myself, but I do and will attempt to warn fellow hobbyists about some critters to avoid. This is one of the poster-child fish which should not be attempted by home hobbyists – they cannot succeed here.

The only other fish in this genus is P. gigas, the Mekong Giant Catfish. It is now endangered due to over-exploitation and habitat destruction. This is the largest FW fish in the world (up to 3 meters for males) and one of the fastest-growing (150 to 200 kg in six years!). Due to its endangered status, we can at least hope that no fry of this one show up in local stores.

Robert T. Ricketts, a.k.a. RTR

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Robert T. Ricketts

Retired research scientist (biochemistry and physiology, pharmaceutical development) and senior process analyst. Started fishkeeping in the dark ages (1950s), first SW tanks in the mid-60s, first puffers in the early 60s. Started with two tanks and never less than multi-tanked excepting some periods in college and grad school. Specialty if any would be filtration and water management. Primarily species tanks, planted whenever possible/practical and some where it not really practical. Ran something on the order of >150 tank-years* in studying optimum tank conditions for F-8 puffers, the largest tank study I have done. Other studies have been significantly less. Alternate canister use was mid-40s, OERFUG just over 60, veggie filters only about 25 to publication, but still going on less intently. If it had been known that the F-8s would live so long, it probably would not have been started at all. *One tank-year is one tank for one year.