maingano cichlid

I have recently started a fish tank which is a 40 gallon feeder that currently has 3 blood parrots, 2 jewel cichlids, 2 firemouths, 3 red zebras and 2 Mainganos. They are all fairly small. However one of the Firemouths seemed to immediately be tentative, but otherwise seemed fine. Then, 4...