I think it would eat your stuff, at least all your crustaceans. However, that said, I have a small undulated in my refugium to be (it's all put together, but the macros have yet to take root, they're starting to now). He hasn't touched the urchins in there, and he also hasn't touched the xenia stalks I've banished there. He has, however, eaten all the copepods, and the bristleworms, etc. etc. He has not, however, as I had hoped he would, started to eat the aiptasia. Obviously, the triggers are found all over the reefs in Hawaii, and they haven't killed off the reef there, but I am sure in a small tank, they would begin to munch on this and that, as they are curious fish. By the way, I have seen them get about the size of 2 hands held together, slightly spread out, or about a foot in length at most. According to my fish atlas, they grow to 35 cm, which is just over a foot. I think any crustaceans or mollusks in your tank would be history, but echinoderms, maybe not with my experience, corals, your guess is as good as mine.
