I like to have a small handful of hermits to eat detritus in pockets that snails can't access. I favor the scarlet hermits, because I think they're more visually appealing than blue claws, though they are typically about 200% more expensive. The big caveat is that hermits are omnivores and it's a virtual certainty that they'll eventually prey on snails, other hermits, badly struggling fish and the occasional coral polyp. That's life on the reef...