My husband has 6 peacock bass and all of them eat very well (rosy red minnows) the problem is that they are all growing well and producing some very nice coloration except one. The other 5 has past him way up in size. He is probably about 2.5in and the others are about 4.5 and 5 in. Is there something I can do to beef him up so he doesn't become food for siblings?