towards what? The blenny or other inhabitants? I'm not sure they pair with blennies, I believe its mostly gobies that they pair with
Also, its like clowns hosting an Anemone - just because you have both in a tank does not mean that they will automatically pair up
As far as other inverts go, I have not had any issues from my pistol shrimp. His pops are annoying as hell in the middle of the night though, which is when he pops most often