I just recently purchased 8 fish for my new 55 gallon tank. I got 4 melanochromis Exasperatus, 2 pseudotropheus Socolofi, and 2 Pseudotropheus Greshakei. Here is my question: I have already lost three fish (under 48 hours of my care, which is one socolofi, and two exasperatus). One Greshakei has taken the largest cave as his territory and chases anyone who comes near. I am almost certain that the three fish missing are from his killing. Now that the tank is less crowded, will he leave the other fish alone, or should I salvage the tank and take him out??