Hi all, new to the forum as well as to the hobby. I got a 20 gal high tank. Stocked with 4 small angelfishes and 2 corys. One Angelfish is aggressive and pick on all 3 of the other ones. My dad has a 30 gallon community tank, so I thought I throw him in there. Now another angelfish seem to take over the role as the aggressor. What should I do?