Anisotremus virginicus belongs to the family of grunts (Haemulidae), a family of fishes consisting of 2 subfamilies in which there are 19 different genera grouping 133 different species. The name of the genus Anisotremus derives from the Greek ‘anisos‘ meaning ‘distinct‘, and ‘trema‘ meaning ‘orifice‘, referring to the two orifices on the chin that serve as sensory organs. The specific epithet virginicus was given in reference to the large number of specimens of this species in the waters of the Virgin Islands. It is a species that lives in the tropical waters of the western Atlantic Ocean, in coral reefs and rocky bottoms, from shallow waters up to 50 meters deep.
The body of Anisotremus virginicus is tall (its height is about half its length), long (maximum length of 40 cm) and laterally compressed. They can reach weights of up to 900 gr. It is characterized by the presence of two pores and a slit between them, which are located on the chin. With these sensory organs, this fish is able to detect the movement of its prey hidden in the sand. It has thick lips and a small mouth. The inside of the mouth is completely red (one of the distinctive features of grunts) and it is equipped with numerous small conical teeth. The preoperculum are finely serrated. As for the fins, the dorsal fin has 12 spines and 16-17 soft rays, the soft portion of the fin being convex. The anal fin has 3 spines and 9-11 soft rays. The pectoral fins have 17 rays, while the caudal fin has a forked shape.
As for the coloration of Anisotremus virginicus, there is a black stripe diagonally from the back of the mouth, passing through the eye and up to the nape of the neck. It has a second black stripe, located behind the head, and which arises before the pectoral fins and at a lower height than the insertion of the pectoral fins on the body. Behind this second stripe, the body has horizontal bands of blue-silver alternating with other bright yellow stripes. Both the head and fins are bright yellow. Juveniles do not have the black stripes of adults, but have two vertical black lines on a white background and a black ocellar spot on the caudal peduncle, as well as the head completely dyed bright yellow.
During the day it is common to find the specimens of Anisotremus virginicus forming banks, where the specimens rest practically immovable next to cave entrances. A characteristic of the family, and therefore of this species, is that they are able to emit sounds by grinding the teeth they have in the pharynx, and amplifying the sound generated thanks to the swim bladder. At night, when this species is most active, it explores the seabed alone thanks to its sensors, in search of its prey, among which we find molluscs, echinoderms, annelids and crustaceans. Their strong jaws easily break the shells of these prey. Juvenile specimens can feed on ectoparasites of other larger fish, and thus function as cleaner fish.
The reproduction of Anisotremus virginicus occurs in the open sea, where after external fertilization, the eggs are left to the mercy of the currents to spread them.
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