So in a week or 2 I'm getting ready to add a few more cichlids in my 125. I bought a canister filter and he threw in a gorgeous adult firemouth male and a large adult featherfin catfish. Will I be safe adding a severum and an electric blue acara and an oscar ranging from 1.5 inch to 2 inches long? The firemouth is 5 inches. Or would I be better off removing the firemouth and buying a baby one to replace him? Thanks in advance!