I had hermits and astrea snails with my toby and dog face and they were fine. The blue spot will not get big enough to break any good sized snail shells. So some scarlet hermits would be a good choice and some snails would be good also. If he eats one a month that no big loss ,which I don't think it will do. Let me say my DF was only 4" so he was not large enough to crunch larger shells. IF you want a shrimp start with a cheap peppermint to see how he makes out.