Black-Bar Chromis (Chromis retrofasciata) Care Guide
Chromis retrofasciata is a small western Pacific damselfish of coral-rich reefs, often seen singly or in small groups near branching corals.
Compiled by Aquairi from published sources · Published · Updated
Overview
Chromis retrofasciata, the black-bar chromis, is one of the smallest chromis, reaching only about 6 cm standard length. It is a western Pacific damselfish of the family Pomacentridae, named for the dark bar across the rear of the body. FishBase places it in the genus Pycnochromis (Pycnochromis retrofasciatus).
Taxonomy
- Family: Pomacentridae
- Genus: Chromis
- Scientific name: Chromis retrofasciata
- Current placement: Pycnochromis retrofasciatus (FishBase)
Habitat
The species ranges from Indonesia to Fiji, north to the Ryukyu Islands and south to New Caledonia. It inhabits coral-rich areas of clear lagoon and seaward reefs at depths of 12-120 m, staying near thickly branching coral for shelter.
Tank requirements
- Minimum tank volume: 200 L
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Specific gravity: 1.024-1.026
- Carbonate hardness (dKH): 8-12
- Group size: keep singly or in small groups
- Adult size: up to about 6 cm
- Lifespan: 8-15 years
Diet
FishBase gives a trophic level of 2.7, indicating an omnivorous diet. In the aquarium small frozen and prepared marine foods offered two times daily are suitable.
Compatibility
A peaceful species that occurs singly or in small groups in the wild and adapts well even when kept alone. It mixes with clownfish, tangs, wrasses and gobies. Aggressive damselfish and predators such as lionfish should be avoided.
Reef compatibility
The black-bar chromis is reef-safe and its small size makes it suitable for nano reef aquariums. It shelters among branching corals and does not harm corals or invertebrates.
Breeding
Reproduction involves distinct pairing, with males guarding and aerating eggs that adhere to the substrate. Captive breeding is considered difficult.
Half-and-Half Chromis Breeding Guide
Overview
Chromis retrofasciata (recorded by FishBase as Pycnochromis retrofasciatus) is a small Western Pacific damselfish from Indonesia to Fiji, reaching only about 6 cm standard length. It occurs singly or in small groups and stays close to thickly branching coral shelter in clear lagoon and seaward reefs. FishBase records it as oviparous with distinct pairing, demersal eggs adhering to the substrate, and male guarding and aeration. IUCN status is Least Concern.
Sexing
External sexual differences are slight, so the sexes are distinguished mainly by breeding behaviour. The male holds and tends a nest among or beside branching coral, while the female approaches to spawn. Because this species is comparatively peaceful and small, keeping several together allows a compatible male and female to associate.
Conditioning
Specimens kept in a stable reef with healthy branching coral and fed frequent small meals come into condition. As a small planktivore associated with coral cover, regular feedings of fine planktonic and meaty foods support egg production while the fish remains close to its shelter.
Breeding Setup
This species' close association with branching coral shapes the setup: the nest is sited on hard substrate near or within coral shelter that the male can clear and guard. Its small size makes it suited to compact reef systems, provided firm substrate for the nest is available within a defensible territory.
Spawning Behavior & Trigger
Following the pomacentrid pattern, courtship involves ritualised displays near the nest, after which the female lays a layer of sticky eggs onto the cleared substrate and the male fertilises them externally. FishBase records distinct pairing during breeding for this species.
Egg & Fry Care
The demersal eggs adhere to the substrate and are guarded and aerated by the male. In Pomacentridae generally the eggs hatch in about two to seven days, and the resulting larvae of roughly 2 to 4 mm pass through a pelagic stage of about a week to more than a month, feeding on very small live plankton such as cultured copepods.
Common Challenges
Despite this chromis being small and relatively peaceful, the pelagic larval phase remains the limiting factor, requiring continuous dense live plankton that home tanks rarely sustain. No species-specific larval rearing protocol is documented, so captive spawning generally ends at the planktonic stage.