As for temporary fishes, I see no reason to be flamed for that, provided you make sure it goes to a good home after you are done... I did this with a Copperband Butterfly, for Aiptaisia, and made sure it went to a quality home... namely my FOWLR tank... ;-)
I have some Dictyota starting in my larger display now... the tank is almost a year old... and I am thinking of an Emerald Mithrax crab... for certain, the Powder Blue tang, the Purple tang, and the Kole tang in this tank dont eat it... although the tank is relatively large (210g) I dont think I want to support another even larger tang (Naso) in there...
Hey Wharfrat, where did you get the Dolabella sea hare... I only find Aplysia sp. available...???