I have a 55 gallon fish tank with 6 fish. One of which is a catfish (not sure what species) and have no problems with and another cichlid that is so hidden I cannot find him. The bluish-white cichlid I pictured attacks this fish frequently and has actually gnawed off all its fins to a bare minimum. The other fish are constantly bullied by this one bluish-white fish. This fish chases, vibrates, and twirls around the other fish. Frankly I am not sure whether I should be concerned with this erratic behavior or not but I am certainly concerned for the fish barely having fins. What should be done to minimize this behavior if needed? Perhaps the temperature? I feed it regularly in small amounts although lately they have not seem to eat as quick as they use to. At the moment the chemicals seem to be fine but the temperature only seems to be a bit high. Thanks!