In general, wrasses tend to be jumpers, so they need a tight fitting lid.
What kind of hermit crab is it? That might be the determining factor. Here are some, in case you don't know what kind it is:
That wrasse needs a minimum of a 70G tank. As the Dragon Wrasse matures it will eat crustaceans, snails, shrimp, starfish, smaller fish, worms, and other invertebrates. (so he might end up eating your whole clean up crew, including the hermit.)
Others will come along and better assist you, since that is all I have read on them....