thanks for that info and your right your tank is alot bigger than mine.always more of a risk with territory in a smaller tank.will get bigger tank in time .usually i wouldnt be that concerned bout trying a new species in my tank but have had aggresion problems before and for last 8months had really peaceful tank and want to keep it that way.got bangaii cardinal,yellow watchman goby,cleaner shrimp,sexy shrimps,zebra hermit,scarlet hermit dwarf blue legged hermit,porcelain crab,pom pom crab,trochus snail,narcissus snail,cerith snail,stomatella,bivalve clams,usual spaghetti worms,bristleworms some kind of limpets and some cool yellowy green sponges that have survived and growing well on my liverock and soft corals.will let you know if i get a pistol