jeanthomasbujard's Identifications

(EN) Sevenstripe Cardinalfish - (FR) Apogon à sept lignes
Mating Ostorhinchus novemfasciatus pair, Tahiti, French Polynesia

The pair colors become much more intense and contrasted during mating: parts that are normally faint yellow turn to heavy gold, the blue markings on the fins become almost iridescent, and the mid-body black stripe can entirely disappear at times.
This mating sequence occured at sunset under a coral boulder that sheltered the pair from the strong current of the nearby coral reef barrier pass - I had to hold on to a large rock to be able to photograph it.