Northern yellow-black triplefin
The northern yellow-black triplefin ("Enneapterygius gracilis"), also known as the northern Australian yellow-black triplefin, is a species of triplefin blenny in the genus "Enneapterygius". It was described by German Ichthyologist Ronald Fricke in 1994. It is a tropical blenny, endemic to northern Australia, in the western Pacific and southeastern Indian Oceans. It is a non-migratory species which dwells in shallow tidal pools on coralline rock and in seagrass, and has been recorded swimming at a depth range of . Male northern yellow-black triplefins can reach a maximum length of 2.8 centimetres (1.06 inches