There are very few laws regarding the fish keeping in Ohio, and the laws that do exist mostly revolve around native and invasive species. However, there are a few ethical considerations that you might want to take note of. Today, I will tell you a bit about three fish that I frequently see for sale in our area which, because of their monstrous adult size, are almost never appropriate inhabitants for a home aquarium. I beg you to leave these gentle giants in zoos, public aquariums, or in the wild, unless you are truly prepared to invest a great deal of time and money into the multi-hundred-gallon system they require.
While working in a local aquarium store, customers often asked why we didn't carry this piranha look-alike. I'd simply spread my hands about a yard apart and tell them, "Well, because they get this big!" and I wasn't exaggerating. This fish, which you can purchase inexpensively as a cute 2" baby (and which are popular because they really do resemble their cousin, the piranha) can reach 36" in length. As a disk-shaped and heavily bodied fish, you're looking at a true tank buster!
To complicate matters even more, they are a schooling fish that needs several companions in order to feel comfortable and safe. You would need a thousand gallon tank to comfortably accommodate just a trio of these giants! Unfortunately, it was impossible to show the true scale of these fish in a photograph, but if you visit the Cleveland Metroparks Zoo's aquatics building, you will find them in the second built-in display on the left.
A better option: If you like the piranha-like appearance of the pacu, silver dollars are a much better option. They rarely exceed eight inches (much more manageable than three feet!) and, like pacu, are mainly herbivorous so you get the piranha look without risking your fingers.
The Redtailed Catfish
While more expensive than pacus, redtailed cats are readily available as juveniles from many area pet stores. This is an undeniably attractive fish, with a boldly marked black and white body, a vivid red tail, and a wiggly, grinning puppy dog persona. These fish have a very endearing personality, often allowing their keepers to "pet" and hand feed them.
However, with an adult length of four feet and weight of one hundred pounds, they require a much larger tank than any but the wealthiest and most dedicated hobbyists are able to provide. With large mouths and voracious appetites, tankmates must be as large as the catfish and, as they require high-quality protein sources, feeding this animal becomes prohibitively expensive. Adult specimens can be observed in the Cleveland Metroparks Zoo's aquatics building in the second built-in display on the left (the same aquarium as the pacu).
A better option: The spotted pimelodus (also known as the pictus cat, among other names), is beautifully patterned and gregarious fish that reaches a maximum length of ten inches. The species I am referring to is silver with black spots and long barbells (whiskers). It is readily available in many local fish stores.
The Iridescent "Shark"
Much sought-after for its shark-like appearance, the iridescent shark is actually a catfish... and it is probably the worst offender in the "inappropriate aquarium fish" category. This is an easily-spooked schooling fish that can reach four feet in length. Its protruding eyes and skittish nature ensure that it is rare to find a specimen in a home aquarium that has reached six inches without developing cloudy or damaged eyes from ramming into aquarium walls or dÃ©cor when spooked. Unless your aquarium is long enough to give several child-sized, fast-swimming fish plenty or swimming space, I would avoid this species.
A better option: The Bala shark (a Cyprinid, not a shark) reaches about fourteen inches, has a more shark-like appearance than the iridescent shark and is much better suited for life in an aquarium. You will still need a large tank, but, again, it is more manageable than the iridescent shark.