Redspot Emperor

Lethrinus lentjan, commonly referred to as the pink ear emperor, redspot emperor, purple ear emperor, or purple-headed emperor, is a species of marine ray-finned fish within the family Lethrinidae, encompassing the emperors and emperor breams. This species predominantly inhabits the Indo-Pacific region.

The species was first formally described as Bodianus lentjan by the French naturalist Bernard Germain de Lacépède, though no specific type locality was provided; it is believed to be Java. While some authors categorize the genus Lethrinus in the monotypic subfamily Lethrininae, with other genera of Lethrinidae classified under Monotaxinae, the fifth edition of "Fishes of the World" does not acknowledge these subfamilies as valid within Lethrinidae. The aforementioned family is categorized under the order Spariformes by the same source.

The specific name 'lentjan' is believed to derive from a local 🇮🇩 Indonesian name for the fish, although Lacépède did not provide an explanation.

Lethrinus lentjan is a substantial species, reaching sizes of approximately 50 centimeters in length, though individuals in intertidal zones may measure about 15 centimeters. It features a distinctive olive-green body, lightening towards the belly, with large diamond-patterned scales. Notable characteristics include a blood-red pigmentation around the gill cover margins and possibly at the base of the pectoral fins. Moreover, the dorsal fin is white with a reddish margin, while both the caudal and dorsal fins exhibit orange mottling. The pectoral fins manifest in hues of pale orange, whitish, or yellowish. It has prominent, fleshy lips and a somewhat protractile snout. The maximum reported lifespan for this species is 19 years.

Geographically, Lethrinus lentjan is widespread across the Indo-West Pacific and adjacent regions, including but not limited to the 🌊 Red Sea, 🌊 Persian Gulf, Great Barrier Reef in northern 🇦🇺 Australia, 🇳🇨 New Caledonia (🇫🇷 Overseas France), the east coast of Africa, and the waters surrounding 🇹🇼 Taiwan.

The species typically frequents coastal environments, especially coral reefs, sandy bottoms, grassy seabeds, mangrove swamps, and deep lagoons. Juvenile specimens are often found in shallower areas in loose groups with adults, while adults tend to be solitary, residing at depths ranging from 10 to 90 meters.

Functioning as a carnivore, Lethrinus lentjan primarily consumes crustaceans and molluscs, including snails, and also feeds on echinoderms, polychaetes, bivalves, worms, and various fishes.

Lethrinus lentjan is subject to both commercial and recreational fishing for human consumption.

Like many marine species, Lethrinus lentjan hosts a variety of parasites. On its gills, it harbors monogeneans such as the diplectanid Calydiscoides difficilis and Calydiscoides duplicostatus, as well as an ancyrocephalid. The gills also contain unidentified gnathiid isopod larvae. Its digestive system is home to several species of digeneans, including the opecoelid Orthodena tropica, plus unidentified anisakid nematode larvae. In 🇳🇨 New Caledonia (🇫🇷 Overseas France), where its parasitic fauna has been studied, Lethrinus lentjan accommodates a total of seven parasite species.