I have an aggressive FOWLR tank and my wife is always looking for me to add things to the tank that would be a nice snack for the boys, so my answer is always the same, "no that would get eaten". I have decided to set up a small (30-40 gal) "critter tank" for her. Its not gonna be fancy, live rock, HOB skimmer and probably a canister filter. Always had FO tanks so I have no experience with other types of livestock. So my question is, what hardy, low maintenance critters would you suggest that should do well in this type of setup? She looking for stuff like crabs, clams, shrimp, starfish, seahorses (probably not gonna happen), hermits etc. Open to all suggestions and comments, thanks.