Well, Here goes: I cycled my tank with 12 (some blue, some yellow-tailed, a domino, and 3 of the striped ones)damsels. I lost 2, but I think they were sick to begin with. After I cycled, I kept meaning to trade them in, and I eventually took all but 3 back. I kept 2 yellow-tailed damsels and a blue damselfish. When I battled ich, I lost the 2 yellow-tailed ones, which made me made. They were docile. So, now I have just the blue one left, and he is one cool guy! He doesn't pick on the yellow tang or clownfish.