Lethrinus rubrioperculatus,the spotcheek emperor, red-eared emperor, red-ears, red-edged emperor, scarlet-cheek emperor, and spot cheek emperor, is a species of marine ray-finned fish belonging to the family Lethrinidae, the emperors or emperor breams. This species has a wide Indo-Pacific distribution.
Lethrinus rubrioperculatus grows to and is brown or olive-grey in colour. It has small, scattered blotches that are irregular in chape. The Body depth 2.94 to 3.18 times in standard length. Body color is olive-gray or brown, with scattered irregular small black blotches. There is normally a red spot present on the top edge of the operculum.[1] The lips are normally red. The fins are pinkish or pale in colour.[2]
Lethrinus rubrioperculatus is found in numerous locations, including East African waters, southern Japan and Taiwan, the Marquesas Islands, New Caledonia[3] [4] and the northern half of Australia.[1] [5]
Lethrinus rubrioperculatus lives over sandy bottoms, in areas where rubble is present, and along the slopes of outer reefs.[1] Although reef-associated, Lethrinus rubrioperculatus also occurs at depths of up to 160 metres, much deeper than most other species in this genus.[6] This species is non-migratory.[2]
Lethrinus rubrioperculatus eats mostly crustaceans, mollusks, echinoderms, and other fishes.[1]
Lethrinus rubrioperculatus is caught commercially.[1]
Lethrinus rubrioperculatus, as in most fish, is the host of many species of parasites.[7] Monogeneans parasitic on the gills include the diplectanid Calydiscoides euzeti,[8] the ancyrocephalids Lethrinitrema gibbus and Lethrinitrema dossenus[9] and several capsalids.[7] Copepods parasitic on the gills include the caligid Caligus lethrinicola[10] and the lernanthropid Sagum vespertilio.[7] The gills also harbour unidentified gnathiid isopod larvae.[7] The digestive tract harbours an unidentified Acanthocephala,[7] unidentified tetraphyllid cestodes,[7] species of the anisakid nematode Raphidascaris (Ichthyascaris),[11] and a variety of digeneans, including the acanthocolpid Stephanostomum aaravi,[12] the hemiurid Lecithochirium sp. and Tubulovesicula angusticauda,[7] the opecoelid Pseudoplagioporus interruptus[7] and three other opecoelids.[7] The abdominal cavity contains two species of larval tetrarhynch cestodes, the otobothriid Otobothrium parvum[7] and the tentaculariid Nybelinia goreensis.[7] In New Caledonia, where its parasites were particularly studied, Lethrinus rubrioperculatus has a total of twenty species of parasites.[7]