Triplefins are tiny blenny-like fishes that skate around over rocks and coral heads on reefs everywhere in the Caribbean. Although a couple of species occur on deeper reefs and walls, most triplefins can be found in shallow water, often on rocks and pilings just below the surface of the water. There is a single Atlantic genus, Enneanectes, presently with eight species, some of which are difficult to distinguish underwater. Prior to 2013, five species were known from the region, but identifications were difficult based on the keys available. In 2013, three new species were described, with the assistance of DNA-barcoding, and a revised key developed. Triplefins on the reef are identified to species mostly by scale patterns and markings, i.e. characters developing after settlement and inapplicable to larvae. Some species are wide ranging, although several have restricted distributions within the Caribbean region. Triplefin larvae share most features and, since there is some overlap in fin-ray counts, it is likely that DNA-sequencing is necessary for most species identifications. Nevertheless, modal fin-ray counts do differ and some larvae from known locations may be narrowed down to one or two candidate species by meristics alone.
Larval tripterygiids resemble the very common small labrisomid larvae, but they differ from all other families by having prominent melanophores on the upper caudal peduncle and three separate dorsal fins. They can be characterized by their pointed snout, long dorsal and anal fins with flexible spines (dorsal fin divided), a short and narrow caudal peduncle, long strand-like pelvic fins, the absence of spines on the head, and light markings (basically a row of melanophores along the anal fin base and along the dorsal midline of the caudal peduncle). Larval tripterygiids have large round eyes, in contrast to many labrids, scarids, and gobies, in which the eye can be small or narrowed.
