Neon Eviota, Eviota atriventris Greenfield & Suzuki 2012

Rowley Shoals, Western Australia, and the entire Great Barrier Reef, Queensland, and some reefs in the Coral Sea. Elsewhere, the species occurs in the tropical east-Indo-west-Pacific from Japan (southern Ryukyu Islands), Thailand, Brunei, Malaysia, Philippines, Palau, Indonesia (NW Kalimantan and Bali eastwards), Papua New Guinea, Solomon Islands, south to Australia and east to New Caledonia.

Individuals or small groups hover above or between the branches of Acropora corals, feeding on plankton in the water column.

Dorsal fin VI+I,8-9 (usually 8); Anal fin I,7-8 (usually 7); Pectoral fin (unbranched rays) 13-15 (usually 14); Caudal fin (branched rays) 11; Caudal fin (segmented rays) 17; Lateral scale rows 23; Transverse scale rows 7.

Fifth pelvic-fin ray 40% or more of 4th ray; 3-5 branches on 4th ray; 4–9 segments between consecutive branches of 4th pelvic-fin ray; embedded cycloid scales on breast; first four spines of dorsal fin filamentous in males, the 4th the longest, extending to caudal-fin base when depressed; genital papilla in male not fimbriate, bilobed at tip and usually extending to or past first anal-fin ray; cephalic sensory-pore system pattern group 2 (only IT missing) (Greenfield & Suzuku 2012).

Body translucent reddish-orange, abdomen black with a bright white stripe running over the black area from the pectoral-fin base to the anal-fin base; a narrow golden line from each eye joining to become a single narrow stripe from the back of the head to the middle of the tail base; a narrow golden line from tip of snout through the top part of the eye and onto the body above the black abdomen; a short golden line through the eye below the pupil. Ventral surface with a golden line from anal-fin origin to tail base; underside a pale translucent cream. Fin-rays reddish-orange, fin membranes with fine dark spots.

Feeds on zooplankton.

Previously misidentified in Australia as Eviota pellucida, a species known only from the Gilbert and Marshall Islands, Ponape, Mariana Islands, and the Ryukyu Islands, Japan.

In Australian waters, the Neon Eviota is most similar to Eviota prasites, which has a distinctive dark spot at the top of the pectoral-fin base, and often a dark spot at the caudal-fin base that is lacking in E. atriventris. E. prasites may also have small red spots on the dorsal and caudal fins, which are lacking in E. atriventris. Unlike most other Eviota species which rest on the bottom, the Neon Eviota hovers just above the substrate.

The specific name atriventris is from the Latin atrus (= black) and venter (= belly), in reference to the black internal pigment on the abdomen.

Bray, D.J. 2020

Atlas of Living Australia