I know this is a kind of an old thread, but I thought I'd quickly share. Zebras are probably the best ones to try. They can absolutely eat inverts, but some will leave everything alone if fed regularly. I have a 3 foot zebra that eats frozen shrimp once every other day. He lives in the same cave as two peppermint shrimp and two pistol shrimp. He has never bothered anything in my tank including peps - pistol - cleaner shrimp, snails, hermits, starfish, and urchins. He also doesn't pay my small fish any attention like my mandarin, yellow watchman goby, and clown fish. The only thing he touched were my crabs, which was expected. Cleaned them out the first day. Other than that - he's a model citizen.