Three-Stripe Damsel Care Guide
Dascyllus aruanus is an Indo-Pacific damselfish with a white body crossed by three black bars, schooling above branching corals but becoming territorial with age.
Compiled by Aquairi from published sources · Published · Updated
Overview
Dascyllus aruanus is a marine damselfish of the family Pomacentridae, described by Linnaeus in 1758. According to Wikipedia it inhabits the Indo-Pacific east and north of the Sunda Shelf. The white body is crossed by three black vertical bars, with a white spot between the eyes, a pattern that gives it the common name humbug damselfish.
Taxonomy
- Family: Pomacentridae
- Genus: Dascyllus
- Scientific name: Dascyllus aruanus
- Author: Linnaeus, 1758
Habitat
Wikipedia reports that the species associates with coral reefs, particularly forming groups above Acropora coral heads in shallow water from about one to ten metres deep. Individuals tend to remain at the same coral patch for life. It is a reef-associated marine fish of the Indo-Pacific.
Tank requirements
- Minimum tank volume: 150 L
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Specific gravity: typical reef salinity (KB GH range 8-12)
- Size: 6-8 cm (Wikipedia max 10 cm, typical 6 cm)
- Lifespan: 5-10 years
Diet
The species is an omnivore and planktivore. Wikipedia describes it grazing on algae and small organisms and acting as a reef gardener through nutrient cycling. In aquaria a varied diet of marine frozen and planktonic foods plus prepared rations is appropriate.
Compatibility
It is highly territorial and aggressive toward unfamiliar species, heavily guarding its chosen coral. It suits robust tank mates such as tangs and wrasses rather than slow or shy fish, and keeping several damsels together in a small tank is not advised.
Breeding
Wikipedia reports that reproduction occurs year-round, with daily mating and females spawning with multiple males in a season, producing up to roughly two thousand eggs per batch. As in other Dascyllus, the eggs are demersal and guarded.
Conservation status
IUCN Red List: Least Concern, though Wikipedia notes vulnerability to climate change and coral bleaching, which threaten its reef habitat.
Three-Stripe Damsel Breeding Guide
Overview
Dascyllus aruanus, the humbug or three-stripe damsel, ranges across the Indo-Pacific east and north of the Sunda Shelf, growing up to about 10 cm with a common size near 6 cm. It lives in small groups of around 30 individuals on shallow coral reefs at roughly one to ten metres and is strongly site-attached and territorial. It is a prolific spawner: mating occurs daily with no defined season, the male builds and guards nests, and uses a 'signal jump' display to attract mates.
Sexing
Damselfishes show little reliable external sexual dimorphism, and Chrysiptera and Dascyllus are not protandrous hermaphrodites in the clownfish sense. D. aruanus lacks clear external sexual dimorphism and lives in size-structured groups around a coral head; the dominant breeding male is recognised by his nest-building and 'signal jump' courtship displays. 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
The male attracts females with rapid 'signal jump' displays above the nest he has built and cleared on the substrate near the coral. Females may produce up to two thousand eggs per batch, with new batches roughly every two days; the adhesive demersal eggs attach to the prepared surface and the male fertilises them externally.
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
Although adults spawn readily and often in captivity, rearing the pelagic larvae is the limiting step and demands a dedicated larval system with live first foods. Adult territoriality and aggression grow with age, so a breeding group needs space and structure. The high spawning frequency means abundant eggs are available for those equipped to attempt larval culture.