hi, i have had a green terror in my 30 gallon tank for a year now with a few other fish and it is at a size of 5.5-6 inches. He is one of my most dominant fishes in my tank. Latley, I have been trying to introduce new cichlids to my tank, but nothing is working out (They are all being eaten). Right now i have a Texan about 4 inches in there who is thrashed pretty bad. what should i do?