Cichlid Aggression?

[MattMcCarlie]

I've had african cichlids for about a year now, no issues until the last few weeks. I've lost 2 yellow labs. Both seemed to have had they skin attacked, they had red marks on them and they tail fins were smaller than normal. I just got back from a 1 week vacation, and noticed the same thing has now happened to one of my red zebras. Skin seems to have been attacked, tail is clearly smaller than others and is floating on the bottom. Lots of pectoral fin movement and seems lethargic. Also, seems to stop moving altogether for a minute or so, then comes back to and starts movement again. I'm worried the fish isn't going to make it through the night. Hoping someone can help me figure out what is going on in the tank. Seems like aggression to me, but I'm still relatively new to the hobby.

Tank is 55 gallon long. I have 4 red zebras, 2 yellow labs, 1 red tailed shark and about 10 cobalt blues.

[limmer]

I would put it into another tank or a separator container in the tank and see if it will recover.
It probably won't make it if you leave in the tank.
One of the others must be attacking it.
Need lots of rock work for hiding or try rearranging rocks.  They are territorial.

[Mike L]

Way to many aggressive fish in the tank. Shark must go for sure. What's going to happen sorry to say is  fish hiding in upper corners. Cichlids are big aggressive bullys. They are establishing territory. You can stock a tank that size with cichlids by choosing species that are compatible.  Pm sent.