well there is a leaf wrasse from raja impat (not sure of spelling) where mangroves grow in clear saltwater over reefs (only place in the world), and the wrasse evolved an elongated dorsal fin to make the fish look like a leaf as it swims.
however, there is another 'leaf-fish' which i am pretty sure is not a wrasse, that is much larger and has a curved body that very closely resembles in looks and swimming style a decaying leaf slowly blowing along the sea floor.
i have never heard of aquarists keeping either of these species.