What foods are you feeding anyway? The gamma color may be a food issue.
I had about 120lbs of live rock and kept the following skrimps (I can spell it right. It's more fun to say it that way though):
Mated pair of CBS, 3 cleaners, 3 fire, 1 pistol (and shrimp goby), and a handful of peppermint. I got lucky with no substantial turf issues and agression. Everyone had their own space it seemed.
Try a watchman goby for your shrimp this time. Maybe one with a little more size on him than the high-fin type. Also, look into blennies and gobies for next additions. Neat and amusing fish. How about 3 blue green chromis?
Gonna need maybe another 50 snails and 30 snails of various types IMO
also. Assuming you got at least 75 lbs of rock or more?