Smooth trunkfish
Smooth Trunkfish
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Tetraodontiformes
Suborder:	Ostracioidea
Family:	Ostraciidae
Genus:	Lactophrys
Species:	L. triqueter
Binomial name
Lactophrys triqueter (Linnaeus, 1758)
Synonyms[2]
Ostracion triqueter Linnaeus, 1758 Rhinesomus triqueter (Linnaeus, 1758)

Lactophrys triqueter the smooth trunkfish, is a species of marine ray-finned fish belonging to the family Ostraciidae, the boxfishes. The smooth trunkfish is found in the Western Atlantic Ocean.

The smooth trunkfish was first formally described as Ostracion triqueter in 1758 by Carl Linnaeus in the 10th edition of Systema Naturae with its type locality given as "India", in error for the Western Atlantic.^[3] The 5th edition of Fishes of the World classifies the genus Lactophrys within the family Ostraciidae in the suborder Ostracioidea within the order Tetraodontiformes.^[4]

The smooth trunkfish is a member of the genus Lactophrys, a name which is a compound of lactaria, meaning a "milkcow", and ophrys, meaning "eyebrow", a reference to the spines above the eyes resembling the horns of a cow. Some fishes in this family are known as cowfishes. The specific name, triqueter, means "three angled", a reference to this fish's triangular body when viewed head on.^[5]

The smooth trunkfish has an angular body sheathed in plate-like scales, growing to a maximum length of 47 centimetres (19 in), though 20 cm (8 in) is a more normal size. The body is enclosed in a bony carapace and, when viewed from the front, is triangular in shape with a narrow top and wide base. The fish has a pointed snout with protuberant lips encircling a small mouth. The tail is shaped like a brush. The general background colour is dark with a pattern of small white spots, often in hexagonal groups giving a honeycomb-like appearance in the middle area of the body. The tip of the snout and the area round the pectoral fins are dark with few spots and the eyes are black. The fins are usually yellowish with a dark base and tips. They have only soft rays with no spines.^[6][7]

The juveniles have dark coloured bodies covered in large yellow spots. As they get older, they develop a pale area where the honeycomb markings will later appear.^[7]

The smooth trunkfish is found down to a depth of about 50 m (164 ft) on coral reefs and over sandy seabeds in the Caribbean Sea, Gulf of Mexico and the western Atlantic Ocean. The range extends from Canada and the Gulf of Maine southwards to Brazil.^[2]

The smooth trunkfish is normally solitary but sometimes moves around in small groups. It uses its protuberant lips to expel a jet of water which disturbs the sandy seabed and reveals any shallowly buried benthic invertebrates. It feeds on small molluscs, polychaete worms, acorn worms, peanut worms, small crustaceans, sponges and tunicates.^[2][7]

In some regions, the smooth trunkfish is caught for human consumption.^[2] It is also sometimes kept in reef aquaria. Caution needs to be used however as it produces a toxic substance, ostracitoxin, in mucous secretions from the skin. When the fish is stressed this is liberated into the water and some aquarium tanks and systems have been poisoned by this with the loss of all the other animal inhabitants.^[8]

• Photos of Smooth trunkfish on Sealife Collection