I keep these cichlids. They are aggressive, but only with their own kind, or with other fish that look similar. They will usually ignore all other fish. The profile says they grow to 4", but they usually do not exceed 3", and can be kept in a smaller tank than most other African cichlids, although I would not recommend anything smaller than a 36" long tank. It is very important to keep these fish in numbers of at least 12. Any less will eventually become just one, as the most dominant fish will slowly pick off all of the others. With numbers of 12 or more, the dominant fish can't focus their attention on any one fish, and the aggression is spread out.