I have purchased 3 red devils to growout in a 75 with hopes of getting a single male in there for life. My question is, are there any easy signs to look for besides one just beating the crap of the other 2? I chose the largest 3 in the tank with male hopes(petsmart) at 4,4, and 5". The bigger one has claimed the main "cave" in the tank, and constantly chases the other 2 around, but no serious harm done. I am assuming this could possibly be my male, but it's also my first rd experience. Anything helps, thanks everyone.