Spiny Boxfish, Lactoria diaphana

Spiny Boxfish, Lactoria diaphana. A rare collection provided by the commercial fishermen of the greater Los Cabos area, September 2011. Length: 14.4 cm (5.7 inches).

The Spiny Boxfish, Lactoria diaphana, is a member of the Boxfish or Ostraciidae Family, and is known in Mexico as cofre espinoso. Globally, there are four species in the genus Lactoria, and all four are residents of Mexican waters, three in the Atlantic and one in the Pacific Ocean.

The Spiny Boxfish has an oblong thick body 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 5 longitudinal ridges: 1 located along the top of their back, 2 on their upper back, and 2 on their lower flank. Their box has openings for the mouth, eyes, gill slits, fins, and tail base. Their head has a small mouth that opens at the front with fleshy lips and 15 mid-sized teeth on each jaw and they have spines before each eye and at the rear end of each lower ridge. Their gill openings are short with oblique slits in front of the pectoral base. Their anal and dorsal fins are set far back on the body; their caudal fin is rounded; their dorsal fin has no spines; and, they do not have pelvic fins.

The Spiny Boxfish is a slow swimmer that is found around coral and rocky reefs at depths up to 135 m (445 feet). Adults are stationary while juveniles are pelagic and sometimes enter estuaries. They reach a maximum of 34 cm (13 inches) in length. They reside in harems of 1 male and 3 or 4 females. They feed on algae, soft corals, crustaceans, sponges, truncates, and worms. They are protected by a toxic slime that helps them avoid predation. The Spiny Boxfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Spiny Boxfish is a resident of Mexican waters of the Pacific but has a limited distribution being found only along the East and West coasts of Baja.

The Spiny Boxfish is unique in appearance and cannot be easily confused with other species with the possible exception being the Spotted Boxfish, Ostracion meleagris (body covered with small white spots).

From a conservation perspective the Spiny Boxfish has not been formally evaluated. They are very small in stature and of limited interest to most; they have also been used on a limited basis to make a nice table decor when allowed to dry.