Blue-streak Damsel (Neoglyphidodon oxyodon) Breeding Guide

Neoglyphidodon oxyodon is an oviparous Western Pacific damselfish that lays demersal eggs on the substrate, guarded and aerated by the male. Pelagic larvae make home rearing difficult.

Overview

Neoglyphidodon oxyodon, the blue-streak damsel, is a Western Central Pacific damselfish of the Indo-Australian Archipelago (Philippines, Indonesia, Ashmore Reef), reaching about 15 cm total length. Juveniles are black with blue and yellow streaks while adults darken. FishBase records it as oviparous with distinct pairing during breeding, following the family's demersal-spawning, male-guarded pattern. IUCN assessed it as Least Concern in 2021.

Sexing

No reliable external sexing character is documented for N. oxyodon in the consulted sources, and colour differences are age-related. As in related damselfishes, the nest-tending male is identified behaviourally during reproduction.

Conditioning

A species-specific conditioning protocol is not documented. N. oxyodon is a herbivore/omnivore (trophic level about 2.7) that gathers in loose groups on current-swept reef flats; a varied marine diet supports condition. Maintain stable reef parameters within the recorded ranges (temperature about 24–26 °C, pH 8.1–8.4).

Breeding Setup

Provide open rock in a reef-style layout with moderate flow resembling the species' current-swept reef-flat habitat, giving a male a defensible nest patch. Following the family pattern, the male clears an area of algae and invertebrates before spawning. Because adults are aggressive, generous space and broken sightlines reduce conflict.

Spawning Behavior & Trigger

Specific spawning triggers for N. oxyodon are not documented. In Pomacentridae, ritualised courtship precedes spawning; the female lays a string of sticky eggs attached to the substrate and the male fertilises them externally. FishBase confirms the eggs are demersal and adhere to the substrate and that males guard and aerate them.

Egg & Fry Care

The male guards and aerates the clutch through incubation. At family level, eggs hatch over about two to seven days into transparent larvae roughly 2–4 mm long that disperse into a pelagic phase. This planktonic stage is the principal barrier to captive reproduction.