Could key hole cichlids be kept with a mated pair or single male firemouth in a 55 gallon tank? There are many caves, and the tank may eventually become planted(I know the firemouths dig). The firemouths currently range from an inch to two inches, there are four of them. All of the firemouths are very chill, except for one VERY agressive one who I will soon be getting rid of. Other current tank mates are 10 black skirt tetras and a bristle nose pleco.