Never had an issue with the current tankmates but I just removed them as my Dovii just bred with a little female I introduced. He was housed with other dominant cichlids before that I had to remove as he got larger. I've kept probably over 200 kinds of cichlids over the last 20 years and Doviis are just mean and that kind of mean can't be bred out of them. The other nastiest cichlid I ever kept based on size was Hemichromis Fasciatus.