I also have a mated pair of tiger pistol shrimp that were in my 3 gallon pico. After my pair of caribean pistols killed my Bicolor Blenny it was the last straw. I switched the pairs and now have my tigers in my main tank and my caribs are by them selves in my 3 gallon. If they are tiger pistols than they are pretty small. Mine are less than inch long each and are pretty tollerant of everybody except a passing hermit time to time, but they are so small they can't do anything. So I would think your tigers would be fine with anything, atleast I haven't had any issues with them.