About Agonus cataphractus (Linnaeus, 1758)
The species Agonus cataphractus, commonly known as Agonus, has the entire head and body covered in hard bony plates. The body plates are jointed to allow the fish to move. A robust curved spine sits on the lower edge of the operculum, and another two-tipped curved spine is located at the end of the snout. The underside of the head has many short barbels. The first dorsal fin has a short base, supported by 5 or 6 flexible spines. The second dorsal fin has a longer base, holding 6 to 8 soft rays. The anal fin matches the second dorsal fin in shape, and contains between 5 and 7 soft rays. This fish has a slender tail that ends in a small caudal fin. Its upper body is dull brown, marked with four dark saddle-shaped patches along the back, while its lower body is pale. The maximum recorded total length for this species is 21 cm (8.3 in), though 14 cm (5.5 in) is a more common adult size. Agonus cataphractus occurs in coastal waters of the northeastern Atlantic Ocean. Its range extends from the southern White Sea, around Jan Mayen, through the Barents Sea, Norwegian Sea, Baltic Sea and North Sea, and reaches south as far as the English Channel. It most commonly lives in inshore waters, and individuals in the Skagerrak move to deeper waters during winter. It usually inhabits sandy substrates, and is occasionally found on stony bottoms. It can be found at depths ranging from 0 to 270 m (0 to 886 ft).
