Diamond Turbot, Pleuronichthys guttulatus

Diamond Turbot, Pleuronichthys guttulatus, Juvenile. Fish caught via hook and line out of a lagoon in Carlsbad, California, February 2020. Length: 3.2 cm (1.3 inches). Catch and photograph courtesy of Ben Cantrell, Poway, California. Identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, California.

Diamond Turbot, Pleuronichthys guttulatus. Fish caught by hand out of Mission Bay, San Diego, California, June 2020. Length: 12.5 cm (5.0 inches). Catch, photograph, and identification courtesy of Ben Cantrell, San Diego, California.

Diamond Turbot, Pleuronichthys guttulatus. Fish caught out of the Lagoon of Torrey Pines State Beach, La Jolla, California, August 2017. Length: 12.5 cm (5.0 inches). Catch, photograph, and identification courtesy of Ben Cantrell, San Diego, California.

Diamond Turbot, Pleuronichthys guttulatus. Fish caught out of the Lagoon of Torrey Pines State Beach, La Jolla, California, August 2019. Length: 18.0 cm (7.1 inches). Catch, photograph, and identification courtesy of Kenneth Tse, Toronto, Canada.

Diamond Turbot, Pleuronichthys guttulatus. Fish caught out of the Lagoon of Torrey Pines State Beach, La Jolla, California, August 2019. Length: 19.0 cm (7.5 inches). Catch, photograph and identification courtesy of George Brinkman, Guelph, Ontario, Canada.

Diamond Turbot, Pleuronichthys guttulatus. Underwater photograph taken in Mission Bay, San Diego, California, July 2024. Photograph, and identification courtesy of Bob Hillis, Ivins, Utah.

The Diamond Turbot, Pleuronichthys guttulatus, is a member of the Righteye Flounder or Pleuronectidae Family, and is known in Mexico as platija diamante. Globally, there are eight species in the genus Pleuronichthys, of which five are found in Mexican waters, all in the Pacific Ocean.

The Diamond Turbot has a diamond-shaped, fusiform, and highly compressed body that are widest in the middle and have a depth that is 52% to 59% of standard length. They are dark gray to greenish with many small brown and blue spots. They are off-white on their blind side and bright yellow around their mouth. They have relatively large eyes on their right side with the top eye preceding the lower eye. They have a small asymmetrical mouth with teeth on both jaws. Their anal fin has 48 to 54 rays; their caudal fin is mid-sized and rounded with a wide base; their dorsal fin originates above the eyes and has 66 to 75 rays; their pectoral fins have 11 to 13 rays; and, their pelvic fins are symmetrical. They have 6 to 8 gill rakers. Their lateral line is straight and over the eyes with 1 branch extending under the lower eye and a longer branch extending under the dorsal fin.

The Diamond Turbot is a demersal species that is found in bays and lagoons from the surf zone over and within sandy and muddy bottoms at depths up to 46 m (150 feet). They reach a maximum of 46 cm (18 inches) in length. As of January 1, 2024, the International Game Fish Association world record stood at 0.68 kg (1 lb 8 oz) with the fish caught in coastal waters off Newport Beach, California in April 2015. They are opportunistic well-camouflaged ambush predators that lie in wait half-submerged on the ocean floor consuming crustaceans and small fish. The Diamond Turbot 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 Diamond Turbot is a resident of Mexican waters of the Pacific Ocean but has a limited range being found from Magdalena Bay, Baja California Sur, northward along the central and northwest coast of Baja. They are also known to be present, but rare, in the northern half of the Sea of Cortez.

The Diamond Turbots can be confused with a series of other Righteye Flounders, including the Hornyhead Turbot, Pleuronichthys verticalis, the Ocellated Turbot, Pleuronichthys ocellatus, and the Spotted Turbot, Pleuronichthys ritteri, but all have elongated oval bodies.

From a conservation perspective, the Diamond Turbot is currently considered to be of Least Concern with stable, widely distributed populations. They are caught primarily as a by-catch of deep water trawlers. They are very difficult to catch via hook and line due to their small mouths. They are small in stature and of limited interest to most.