I have a 65 gallon (tall) reef tank with only a peacock mantis shrimp (griffin) in it. I was considering adding a few damsels. Putting aside whether or not the peacock will attack the fish, what is a good number. I was considering three yellow tailed but not sure if three would be too fwe? too many? I had read an odd number is the appropriate odd/even amount but not sure if three is good. Thanks for the help all.