I have a sargassum trigger in my tank, and he is definitely not a model citizen, but he tends to stay away from snails unless I had removed some from the tank and put them back, if it's in the water column it will at least try to eat it. This also applies to new small fish that are added. I have a fairly diverse cleanup crew of snails, dwarf ceriths, FL ceriths, Euplica snails, nerites, keyhole limpets, zigzag periwinkles, stomatellas, astrea, and probably more that I am missing. I also have a strawberry crab and a couple of larger hermits that the trigger doesn't go near. One of the hermits molted recently and I picked up the molt and put it in the water column to see if the trigger would it eat and he nibbled, but then spit it out and didn't go for it again, so it must not like it and explains why the hermits still live :)