unicornfish with a distinctive horn swimming in the reef

acanthuridae actinopterygii animal aquarium aquatic bluespine coral exotic fauna fish fishes forehead head hexacanthus horn indian life marine naso natural nature nose ocean one pacific perciformes protrusion protuberance reef rostral sea sealife short shortnose surgeon surgeonfish swim swimming tang tropic tropical undersea underwater unicorn unicornfish unicornis water waters wild wildlife