Cichlid selection help

Nothng, your tank is overstocked/incorrectly stocked right now. The 2 oscars and the pleco have A 90 gal. tank over loaded. If either the oscars of the comvict start to breed you going to have real problems. The oscras are a non aggressive SA cichld that can reach 14 inches and perfer softer acid water. The convicts a aggressive CA cichlid that max out at about 4 inches, and the jewel is a small african that has a totally different water and diet needs then any of the others. Now If this tank is 5 feet long 90 gals. it's probably now wide enough to house the oscars (standered 90 is 4 feet long). Perfecto makes a 120 gal. tank that is 5 feet long by 18 inches wide. A 5 foot long 90 would be a custom built or odd sized tank. I would decide what type of cichlid you want to keep (SA, CA, african,) and get rid or move the rest.