You can put 10 to 15 cichlids in a 55-gallon aquarium. With that said, it all depends on what type of cichlid you have. Cichlids are a very diverse fish family – some varieties are tiny, but some are huge. As a general rule, a two-inch cichlid requires ten gallons of water to live comfortably. So, the bigger the cichlids, the fewer you can fit in a tank.
For example, African cichlids grow to be around six inches long, so you can fit up to ten African cichlids in a 55-gallon aquarium. Meanwhile, mature dwarf cichlids are only 3.5 inches long, so you can fit 15 of them in a 55-gallon tank.