I don't have one, but read before that when large enough they can pick on or catch slow and small enough fish or inverts (might pick on snails). I'm sure those fish will be fine. Could probably catch a small goby if they were hungry enough. I don't think the engineer goby would eat the arrow crab, but don't have one so wouldn't know. I read numerous times that coral banded shrimp ARE mean. Will pick on fish and I think even corals. It's a gamble b/c there's always different personalities and scenarios.