In some parts of Florida it may be possible for Piranha to exsist - that's part of the reason Floridians can't own them. They are not native to Floridas water ways and may or may not destroy it's eco-system in some fashion if released, this is what the state is trying to protect against. I'd find it hard to believe that P's could survive in whats classed non-tropical or cold water ways like Bass, Trout, Sunfish, etc.. or in the waterways that contain a high volume of salinity in FL- The Everglades however may be prime for this type of fish and knuckle headed human beings who think "it would be cool" to fish for Piranha in Florida would release them into the wild if given half a chance.
I'm not saying you would, however I'm sure theres plenty of ppl who would and already have. I'd think that one reason a person would want to be a Marine Biologist would be to save the natural enviorment and study it as nature intended. @ 13 you have much to learn, don't be discouraged by those who use the internet to mock you hoping it makes them look cool - it doesn't. Right now if I were you I'd be more concerned with my current stock of fish. Your 55 is too small for some of the cichlids your keeping, it's also grossly overstocked - turtles kill fish - and your Arrowana needs a body of water that exceeds the total volume of all 3 of your tanks. They grow rather quickly to over a foot in length.
