Spiny Boxfish, Lactoria diaphana
The Spiny Boxfish, Lactoria diaphana, whose common Spanish name is cofre espinoso, is a species in the Family Ostraciidae, the Boxfishes, known as peces cofre. Globally, there are only four species in the genus Lactoria, with all four is found in Mexican waters, three in the Atlantic and one in the Pacific.
The Spiny Boxfish have oblong thick bodies that are enclosed in a bony box formed by thickened, joined, enlarged, and hexagonal scale plates. They have a gray to pale brown coloration with indistinct dark blotches. They have wide round bellies with five longitudinal ridges; one located along the top of their back, a pair on their upper back, and a pair on their lower flank. They have spines before each eye and at the rear end of each lower ridge. Their box has openings for the mouth, eyes, gill slits, fins, and tail base. Their small mouth opens at the front with fleshy lips and 15 mid-sized teeth on each jaw. Their gill openings are short with oblique slits in front of the pectoral base. Their anal and dorsal fins are at the rear; their caudal fin is rounded; and their dorsal fin has no spines. They are devoid of pelvic fins.
The Spiny Boxfish are slow swimmers found around coral and rocky reefs at depths up to 445 feet. Adults are stationary while juveniles are pelagic and sometimes enter estuaries. They reach a maximum length of 34 cm (13 inches). They reside in harems of three or four females and one male. They are protected by a toxic slime that can kill other fish, thus making them unsuitable for use in aquariums. They feed on algae, soft corals, crustaceans, sponges, truncates, and worms. In Mexican waters they have a limited distribution and are only found along both coasts of the Baja.
The Spiny Boxfish is unique in appearance and cannot be easily confused with other species, however, it is somewhat similar to the Spotted Boxfish, Ostracion meleagris (body covered with small white spots).
The Spiny Boxfish are very small in stature and of limited interest to most but make nice table decor when allowed to dry.