I have had mine since it was 2 inches 4 or 5 years ago, it is now about 20inches.I raised it in smaller tanks until around the 6inch length,then it lived with a Tanganycan Oreochromis in a 125.The Oreo. was bigger and they both only were fed various pellets but the Emp. did not really grow until after the oreo died for some reason[ maybe age]. Then over time it got to the point where it couldnt turn around in the tank unless from a diagonal position. The Emp now resides in my 180 which was purchased about two years ago.His tankmates are other cichlids from the two lakes including a pair of Champsachromis Caerulius he does not bother the others until feeding time,he then chases all of them away from the pellets. He once splashed the water with his tail to scare away the other fish and caused anice puddle on the floor.I dont think they reach full size in any but the biggest tanks but you can still get a nice size and full color in a good size tank .