if i’m not mistaken, you’re trying to identify this fish. it looks as if this is a ‘small triplefin’ (tripterygion melanurus). it can also be a ‘triplefin’ (tripterygion sp.), hard to tell from the picture. besides i’m not exactly a marine biologist .

i’ve seen this little guy plenty of times diving at the mediterranean coast of turkey. friendly little reef dweller, who likes to crawl on rocks with its pointy pectoral fins.