Camouflage Grouper

The camouflage grouper (Epinephelus polyphekadion), also referred to as the blue-tailed cod, or camouflage rockcod, is a marine ray-finned fish belonging to the subfamily Epinephelinae within the family Serranidae, which also includes species such as anthias and sea basses. It is widely dispersed throughout the Indo-Pacific region and is typically associated with reef environments.

Morphologically, the camouflage grouper features a body whose standard length is approximately 2.7 to 3.1 times its depth. The interorbital space is flat, while the dorsal profile of the head is convex. The preopercle is rounded, with slightly enlarged serrations at the corners, and the gill cover displays a notably convex upper edge. The species possesses a dorsal fin with 11 spines and 14 to 15 soft rays, alongside an anal fin with 3 spines and 8 soft rays. Characteristically, the fourth spine in the dorsal fin exceeds the others in length, and the membranes between the dorsal fin spines are subtly notched. Additionally, the caudal fin assumes a rounded shape. This species exhibits a pale brown coloration with small dark brown spots, a whitish upper body interspersed with large dark blotches resembling diagonal bands, and a distinct dark saddle-like mark at the base of the caudal fin. Frequently confused with Epinephelus fuscoguttatus, the camouflage grouper can grow to a maximum total length of 90 centimeters (35 inches) and inhabits depths ranging from 1 to 50 meters.

The distribution of the camouflage grouper spans the Indo-Pacific, from the East African coast extending from the 🌊 Red Sea south to 🇲🇿 Mozambique, eastward across the 🌊 Indian Ocean to the Comoros, British 🌊 Indian Ocean Territory, 🇲🇺 Mauritius, and the 🇸🇨 Seychelles, reaching as far east as 🇵🇫 French Polynesia. In the Pacific, its range stretches north to southern 🇯🇵 Japan and southward to 🇦🇺 Australia, where it is present from Shark Bay and Scott Reef in Western Australia to One Tree Island in Queensland, and around the reefs and islands of the Coral and Tasman Seas.

Ecologically, the camouflage grouper inhabits lagoons and outer reef areas in shallow waters rich in coral. It is more populous around islands, particularly atolls, and prefers environments with caves and crevices. Typically found in small schools, it can also be solitary and thrives in clear water areas. As a predatory species, its diet predominantly includes crustaceans, especially portunid crabs, and fish, with occasional consumption of cephalopods and gastropods. It is presumed to be gonochoristic, although hermaphroditism remains undemonstrated. Attaining sexual maturity at approximately four years of age, the species can live up to 42 years, forming spawning aggregations and following regular migratory paths to reach these sites.

Formally described as Serranus polyphekadion in 1849 by Dutch physician, herpetologist, and ichthyologist Pieter Bleeker (1819–1878), the type locality was recorded as Jakarta.

Historically prevalent in Zanzibar fish markets, the camouflage grouper holds significant value in the international live reef fish trade across Southeast Asia, the western Pacific, and 🌊 Indian Ocean regions. Most captures occur during spawning aggregations, with primary exporting countries being the 🇵🇭 Philippines and 🇮🇩 Indonesia. A notable commercial fishery exists along the southern 🌊 Red Sea coast of 🇸🇦 Saudi Arabia. Fishing methods include hook-and-line, spears, and traps, particularly in 🇦🇺 Australia and Papua 🇵🇬 New Guinea. While hatchery production has been attempted, it has yet to achieve commercial sustainability.