im knew to this. have had a 20 gallon setup for 3 months know with 4 juvenile african cichlids, just purchased a 60 gallon tank two weeks ago and lettin it cycle, now, this fish in the picture has killed all my cichlids which include a juvenile giraffe hap, and two juvenile electric yellows. all four fish were write around the same size when i bought them, but this one got 3 times the size, so i want to know, what is it and what is it compatible with!?????!!!