The rainbow wrasse is a small and colourful labrid fish with an oblong, laterally compressed body and marked sexual dimorphism. Males display bright blue, green, and orange colours, particularly during the breeding season, whereas females are more subdued in appearance, with brown and beige tones. This species commonly inhabits shallow coastal habitats, including rocky bottoms, Posidonia oceanica seagrass meadows, and sandy areas with algae. It is mainly active during the day and feeds on small benthic invertebrates such as crustaceans, molluscs, and polychaete worms. Rainbow wrasses exhibit diurnal and territorial behaviour, particularly during the reproductive period.

An interesting reproductive strategy occurs in this species. Two types of males are present: territorial males and satellite males. Satellite males resemble females in coloration and remain close to the nesting areas defended by territorial males. At the moment of fertilisation, they quickly approach and release sperm to fertilise some of the eggs. This “sneaker” strategy allows them to reproduce while minimising energy expenditure and reducing the risk of predation associated with the conspicuous mating displays of territorial males.