Well, I assume you are talking about the Indo-Pacific Tarpon (Oxeye Tarpon, Oxeye Herring) They can reach almost 3 feet, are very skittish fish, can live in salt or fresh water, and need a lot of space...more than most fish of their size. They constantly swim, and never rest on the bottom. They are also air breathers, like Snakeheads, Bettas, and Arowanas. They might do stupid stuff like smash into the glass or even jump if they are startled.