What's the species? That's the only way to tell. Hogchockers Trinectes maculatus are freshwater and are occasionally available in stores. They do relatively well in aquaria, but require some attention. They need a room-temp tank. They will take live foods like shrimp, and worms (depending on size). If they make it long enough to reach a decent size, they may eat some feeder fish (but I wouldn't recommend that if they are small). A colleague of mine keeps some and they were eventually trained to take chunks of frozen market shrimp and chopped up earthworms.
Support your local ichthyofauna - buy a fishing license!