Blue Damsel Fish Mating Habits

The blue damsel is found in sheltered lagoons and on subtidal reefs in the West Indian Ocean. This vividly colored little marine fish lives in small groups consisting of an adult male and several females or juveniles. Adult males possess a bright yellow or orange snout and tail, which immediately distinguishes them from both juveniles and females. Female blue damsels lack the bright facial and caudal color of the mature male and are an overall vivid blue color, with a black spot on the base of their dorsal or back fin. Juvenile blue damsels have the same coloration as the adult female fish. This belligerent little damsel is an egg-depositing species.

  1. Substrate Spawners

    • Unlike many coral reef species, the blue damsel, like other members in its family, is a demersal or substrate spawner. The pugnacious male blue damselfish establishes a territory, in which he prepares a suitable spawning site. This fish chooses a rocky ledge or the surface of a coral skeleton and removes algae and other debris by biting at it. The damselfish cleans an area large enough to accommodate the adhesive eggs which will be laid by the female.

    Attracting a Female

    • Male blue damsels attract the attention of gravid females by engaging in erratic swimming behavior and by changing colors. The male may also vocalize at this time. These tactics draw one or more female blue damsels into the male's territory. A female which accepts the male's advances will lay up to 20,000 adhesive eggs on the site which the male has previously prepared. The male fish will then swim over the nest and fertilize them by spraying milt or sperm over the eggs.

    Additional Females

    • The mating process, from the time the female accepts the advances of the male until the male fertilizes the eggs, lasts up to 20 minutes. Additional females may accept the attention of the same male. The male will fertilize all eggs that have been laid and begins to tend the eggs thereafter.

    Egg Tending

    • The male blue damsel will fearlessly guard the developing eggs. Blue damsel males will protect their nest against creatures much larger than themselves. The eggs hatch between three and seven days. Once they hatch, the larvae are carried to other areas of the reef by the currents. These larvae predate on both zooplankton and phytoplankton which are carried with them by the tides.