Thats a lunar wrasse.
Had one in my 150 for severals years. Bought him small and he grew big and beautiful and are very interesting fish with alot of personality.
HOWEVER these are some of the most agressive tank destroying fish you can have. He was the last fish i could add because he killed anything i added including a large emporer anngel. All the fish that were in there when i added him he never messed with including small gobies but you will NEVER be able to add any other fish including triggers puffers and groupers. Even fish much larger are in danger. He will swim bye at lightning speed and take an eye out of your fish and just keep coming back. He also flipped really large rocks over by putting his tail under em and wacking em. Always searching for stuff underneath. Feeding your anenome is over. Even if you put a container over it he will knock it off and take food literally out of its stomach. He never ate corals but will flip over rocks they are on and they wont like that. Your asand bed will also be a mess as he boars down in sand all the time not just for sleep but for kicks.. and good luck catching him cuz they are pretty smart. Tried for years and caught every fish in my tank but him. I would add these last even to a big predator tank to be honest.
