the one I have is 23" and just went into a pond with 2 other hybrids. He is definitely the most aggressive. They all lived together in harmony in their previous owner's tank. Now I have them in an indoor pond, and I guess they are just trying to establish territory or something, but the tsn x rtc is extremely aggressive to the others. So be warned if you do get these fish, to me they seem more aggressive than their full blooded parents, and my hybrid is definitely personable. Very docile to me. I can rub his head and under his chin. Can't wait till their stress levels come down so they will eat again.