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Sharks in the Bathtub--A Bad Idea!

Some people think sharks are ideal for their home aquarium. Maybe it's the idea of having a "man-eater" in the house. This is a myth; no sharks are "man-eaters" in the sense that they will intentionally attack a human. Most shark attacks are due to the shark confusing a human with its natural prey. Or perhaps shark ownership is some people's strange way of "getting back" at a "dangerous" species. This is another myth. Sharks are not "dangerous." They are simply sharks, and will do what they need to do against perceived threats. What sharks do is part of their natural behavior, and it is not aimed at humans specifically. Maybe keeping a shark makes an owner feel more "macho" (or the female equivalent thereof.)

It is my opinion as a senior aquarist that any responsible, ethical hobbist will pass sharks by. Many sharks sold at pet stores or online get far too large for most home aquariums. Nurse (Ginglymostoma cirratum), black tip reef (Carcharhinus melanopterus), epaulet (Hemiscyllium trispeculare), wobbygong (Orectolobus spp.), leopard (Triakis semifasciatus), and horn (Heterodontus spp.) sharks can grow between 3.25 feet to over 13 feet long. One local wholesaler I know even considered selling bull sharks (Carcharhinus leucas)--one of the most aggressive sharks around. They can grow to 10 feet long and are sometimes found in freshwater. (Thankfully, this insane exercise never came to pass!)

Most sharks require a tank ranging in size from 6 X 4 feet to one the size of a swimming pool. Even the relatively smaller catsharks (Chiliscyllium spp.) which are 3.25 feet to about 8 feet long, require a 12 X 6 foot tank; I am basing these sizes on first-hand observations of several shark species in captivity.

Notice I haven't mentioned tank size in terms of gallons? For sharks and other overly-large fish, one must consider SURFACE AREA or CUBIC FEET of unobstructed swimming area over gallonage. In the case of non-benthic (non-bottom dwelling) sharks, such as the black tip reef, it's important to provide as much cubic space of swimming room as possible, preferably in a round or oblong tank so the animal doesn't bash itself into corners.

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"But Frank," you may say, "it's a small shark." Yes, it will be small at first. But, as with all living things, they grow. "But it will only grow to the size of it's tank, right? No, it won't. Some fishes, notably salmonids, can be stunted for a period of time by the size of their tank. Sharks aren't like that. They'll keep growing until their environment becomes so unsuitable that it dies.

So? If it gets that big I'll give it to the Aquarium." No. Public aquariums have more than enough sharks; most public aquariums--including the New York Aquarium--strongly discourage "donations" of sharks. I can't tell you how many calls we get each year from hobbyists whose sharks--especially nurse sharks-have out-grown their tanks. Or their owner's bathtub.

Fine. If the aquarium doesn't take it I'll just through it in the river or set it free at the beach.

Don't even THINK about releasing a long-term captive shark-or fish of any kind-into local waters! Releasing ANY animal into its non-native environment is both unethical (for the animal will surely die) and illegal.

In addition to sharks, other cartilaginous fish that don't make for good pets include rays and guitarfish. These, too, often get too large to be housed properly by the average aquarist. Even smaller species like the yellow stingray (Urobatis jamicensis) require a minimum water surface area of 4 X 2 feet. Others, like electric rays (Torpedo spp., Narcine spp., Narke sp., Hypnos spp. And Trygonorhina sp.), blue spotted rays (Taeniura spp.) and guitarfish (Rhinobates spp.) hardly ever eat in captivity, and slowly starve to death. With over 900 species of fishes imported for the ornamental trade, would we really miss sharks if they were no longer imported for sale? Sharks are simply unsuitable for the average aquarist. No responsible, ethical hobbyist would even consider them, and no responsible, ethical shop would stock them.

Have a fish question for Frank? Log on to news:// or email him directly at Visit his live fish chat every Sunday from 9pm to 10pm at mic://

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