I have an extra 75 gallon tank with 2 emperor filters, I am looking for a fun aggressive fish or 2, something that gets decent size but not outgrow a 75 gallon. was thinking red tail cat till i realized it would eventually outgrow my 75 gallon. anything in that type or close by that you can think of, want to do a lot of research on the fish before i get it, but not sure what i want