Three-Spot Damsel Care Guide
Dascyllus trimaculatus is a hardy Indo-Pacific damselfish whose juveniles shelter in anemones and whose adults become strongly aggressive.
Compiled by Aquairi from published sources · Published · Updated
Overview
Dascyllus trimaculatus, the three-spot or domino damsel, is a marine damselfish of the family Pomacentridae. It reaches about 14 cm in total length. Juveniles are dark with three white spots and shelter in anemones, sea urchins or coral heads; adults turn grey to black and become strongly aggressive.
Taxonomy
- Family: Pomacentridae
- Genus: Dascyllus
- Scientific name: Dascyllus trimaculatus
Habitat
According to FishBase, the species is distributed across the Indo-Pacific from the Red Sea and East Africa to the Line and Pitcairn islands, north to southern Japan and south to Sydney, Australia. It is reef-associated and recorded from the surface to about 55 m. Adults form small to large aggregations around coral heads and rocks, while juveniles associate commensally with large sea anemones, sea urchins or small coral heads.
Tank requirements
- Minimum tank volume: 200 L
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- GH: 8-12 °dGH
- Lifespan: 5-10 years
Diet
The species is omnivorous. FishBase reports stomach contents including algae, copepods and other planktonic crustaceans. In captivity it readily accepts a varied diet of meaty and prepared marine foods.
Compatibility
Adults are aggressive and recognise conspecifics partly by sound. They suit robust tankmates such as tangs, wrasses and triggers (with caution), and should not be combined with slow, shy fish or other small damsels in confined tanks. Because it does not harm corals or invertebrates, it is generally considered reef-safe.
Breeding
FishBase describes the species as oviparous with distinct pairing. Eggs are demersal and adhere to the substrate; males guard and aerate them. Courtship includes male signal-jumping, and captive pairs may spawn around three times a month.
Conservation status
IUCN Red List: Least Concern (assessed 2021).
Three-Spot Damsel Breeding Guide
Overview
Dascyllus trimaculatus, the three-spot or domino damsel, is native to the Indo-Pacific from the Red Sea and East Africa to the Pitcairn Islands, reaching about 13 cm in the wild and up to 14 cm in aquaria. Juveniles are dark with white spots and shelter among anemones such as Stichodactyla mertensii, urchins or branching corals, an association lost as they mature into grey-to-black adults. It feeds on algae, copepods and other planktonic crustaceans, and as a damselfish spawns demersal eggs guarded by the male.
Sexing
Damselfishes show little reliable external sexual dimorphism, and Chrysiptera and Dascyllus are not protandrous hermaphrodites in the clownfish sense. D. trimaculatus has no reliable external sex difference; a breeding male is recognised behaviourally by his preparation and defence of a nest site within the group's territory. In practice a compatible male/female pair is identified by behaviour once a hierarchy forms, with the dominant male defending a nest site.
Conditioning
Damsels are hardy omnivores; conditioning relies on varied feeding (frozen and prepared marine foods plus some algae) and stable reef water. Because most species are aggressive, a breeding pair is best given its own territory with ample rockwork so the male can establish and defend a nest site without constant conflict.
Breeding Setup
- Compatible established pair given its own territory
- Temperature 24-26 C, pH 8.1-8.4, stable salinity
- Hard substrate (rock, rubble or shell) for the demersal egg patch
- Plenty of rockwork and hiding places to defuse aggression
Spawning Behavior & Trigger
Breeding follows the damselfish pattern: the male clears and prepares a hard nest surface, the female deposits a patch of adhesive demersal eggs that attach to the substrate, and the male fertilises them. As one of the larger Dascyllus species it can be markedly aggressive when defending a nest.
Egg & Fry Care
The male performs the parental care, guarding the nest and aerating the eggs until they hatch. Across the family Pomacentridae the eggs hatch after about two to seven days depending on species and temperature. Newly hatched larvae measure roughly 2-4 mm and enter a pelagic stage that, depending on species, can last from about a week to more than a month before the young settle and take on juvenile colours.
Common Challenges
Rearing the pelagic larvae is the principal challenge and requires a dedicated larval system. The strong adult aggression of this comparatively large damsel makes pairing and tankmate management difficult, so a breeding pair is best isolated. Larvae are small and require live first foods such as rotifers before Artemia.