Halichoeres poeyi has a relatively long, thin body, a large eye and a pointed snout with a terminal mouth which has protruding canine-like teeth. The pectoral fins extend to the vent. It has wide pink bands and a narrow blue stripe on the head and tail and there is a dark spot behind the eye which gives it the common name of black-ear wrasse. The background colour of the head and body is olive with pinkish-red lined scales. The margin of the dorsal fin is blue and orange and the caudal fin is dull yellow with diagonally converging blue and rose lines. The males and females are similarly patterned but males are larger than females. There is another black spot on the spine near the origin of the dorsal fin. The dorsal fin has 9 spines and 11 soft rays; the anal fin has 3 spines and 12 soft rays. The maximum size of H. poeyi is around 20 cm in length
Halichoeres poeyi occurs in coral and rocky reefs and also in seagrass, especially turtle grass beds at around 30m in depth. It is frequently encountered in areas rich in algae as well. This species is strictly diurnal in nature and is lethargic during the hours of darkness. It feeds mainly on invertebrates such as decapods, gastropods, sea stars and sea urchins, it is assumed that sea urchins are scavnged after they are predated by larger predatory fish.
H. poeyi is a sequential protogynous hermaphrodite, every individual begins life as a females but some fish change sex from female to male as they grow, the average body length at which this takes place is 8.3 cm. The males gather in leks and display showily in an effort to attract females and is this unusual among the wrasses as in most other species the males form harems. Larval H. poeyi are long and thin and have a small mouth and small pelvic fins. H. poeyi is the only species of Halichoeres where the larvae develop internal, specialised, chromatophores.
Halichoeres poeyiis generally of little interest to fisheries due of its small size but it is traded in the aquarium trade and in Brazil a quota has been imposed since 2004 on companies who catch this species for that trade, that quota is 1000 fish per annum per company.
- L. Rocha; R. Francini-Filho; M. Craig; et al. (2010). "Halichoeres poeyi". The IUCN Red List of Endangered Species. International Union for Conservation of Nature and Natural Resources. Retrieved 17 February 2017.
- "Synonyms of Halichoeres poeyi (Steindachner, 1867) )". Fishbase.org. Retrieved 17 February 2017.
- Raéann Parris (2016). "Halichoeres poeyi (Blackear Wrasse)" (PDF). The Online Guide to the Animals of Trinidad and Tobago. University of the West Indies. Retrieved 18 February 2017.
- "Blackear Wrasse". Snorkel St John. Retrieved 18 February 2017.
- Rainer Froese; Susan M. Luna (2016). R. Froese; D. Pauly, eds. "Halichoeres poeyi (Steindachner, 1867)". Fishbase. Retrieved 18 February 2017.