This unusual reef fish has an armor of heavy hexagonal scales covering much of its body, and an elongated caudal peduncle (tail stem) with rounded fins. It has a small, puckered mouth and tiny ‘horns’ over its eyes, with a sloped face and pronounced forehead, giving it its bovine name.
Order – Tetraodontiformes
Family – Ostraciidae
Genus – Acanthostracion
Species – polygonius
Common Names: Common names in the English language cowfish and trunkfish. Other common names include baiacu-de-chifre (Portuguese), botelia (Spanish), coffre polygone (French), cofre (Spanish), peixe-cofre (Portuguese), peixe-vaca (Portuguese), torito (Spanish), torito hexagonal (Spanish), and torito panal (Spanish).
Habitat: The cowfish live in the clear waters of coral reef habitats at depths of 10-262 feet (3-80 m).
Distinctive Features: The triangular body is nearly enclosed in a “carapace” consisting of thickened hexagonal scale plates that are firmly attached to each other with the exception of the cheeks to allow for respiration movements. There are openings in the carapace for the mouth, eyes, gills, fins, and the flexible caudal peduncle.
There is one pair of scales in front of the eyes. The terminal mouth is small with fleshy lips and the gill openings are short with slits located in front of the bases of the pectoral fins. There are no pelvic fins and the caudal fin is distinctly rounded.
Dentition:
The teeth of the cowfish are moderate and conical in shape with usually less than 15 teeth in each jaw.
Size, Age, and Growth: The maximum length of the cowfish is 19.7 inches (50.0 cm) total length (TL), although it more commonly reaches lengths of 9.8 inches (25.0 cm) TL.
Food Habits: The honeycomb cowfish feeds on marine invertebrates including shrimp, tunicates, and sponges.
Reproduction: Very little is known about reproduction within the family Ostraciidae. However, it has been observed that this species forms social harems consisting of one male along with only two females.
Predators: Larger fish are potential predators of the cowfish, however it may be undesirable as a prey item due to its protective external armor, the carapace.
Parasites: Three monogeneans parasites have been reported from the cowfish: Haliotrema minutum, H. torridum and H. kritskyi nom. nov.
