Chromis viridis
Green chromis
A small damselfish (family Pomacentridae), known in Italian as castagnola blu verde, with a pale blue or green body. It forms large schools above branching corals in sheltered areas. 1 2 3 20 It lives from the Red Sea and East Africa to the central Pacific. 2 7 It is the most imported marine ornamental fish in both the United States and the European Union. 12 13
At a glance
Data from the scientific sources listed at the bottom.
Depth in the wild
1–20 m
Size
up to 10 cm
maximum total length according to FishBase; Reef Life Survey gives 8 cm
Temperature in the wild
21.4–31.1 °C
Where it lives
Indo-Pacific: from the east coast of Africa to the Line Islands and the Tuamotus, north to the Ryukyu Islands and south to the Great Barrier Reef and New Caledonia. 2 It is also found in the Red Sea and the Gulf of Aden, where in a survey across five countries it was the most abundant ornamental species (54.4% of the individuals counted). 7
Conservation
IUCN Red List: least concern (2021). Red List data taken from FishBase and GBIF. 2 15 It does not appear in the CITES lists checked on Species+. 16 A review of the European trade, however, reports that the wild population is declining and that the number of specimens imported into the EU fell by about 70% over the eight years studied. 13
Life in the wild
Where it is found
Sheltered areas such as permanently submerged reef flats and lagoons, above thickets of branching Acropora corals. 2 At Moorea it mainly occupies Pocillopora corals. 6 At Okinawa it is found in inner areas with plenty of sand and is considered tied to live coral: over 80% of individuals were associated with it. 8
What it eats
It feeds on zooplankton in the water just above the coral and hunts its prey by sight. DNA found in the stomachs of fish from Moorea shows a less varied diet than that of the related species Dascyllus flavicaudus, with a tendency to choose larger prey, such as the large copepod Labidocera. 6 FishBase, on the other hand, lists it as a phytoplankton feeder. 2 More of them gather above an Acropora colony when wind and water level rise: perhaps they move away from shelter to reach food carried by the current. 9
Behaviour
Active by day; at night it stays almost still. 2 10 Juveniles are tied to single coral colonies, while adults form large groups. 2 The school has a measurable calming effect: the sight and smell of companions lower the minimum oxygen consumption, while after a week alone the fish's condition gets worse. 10 According to a study on the Great Barrier Reef, fish from areas with strong currents have more effective escape responses. 11
Reproduction
It lays eggs that stick to the bottom. Males prepare a nest on sand and rubble that is used by several females; the eggs hatch in 2-3 days while the male guards them, fans them with his tail and eats those that do not hatch. It matures at about 5.8 cm. 2 At Eilat the larvae prefer to settle on certain Acropora colonies, especially those already hosting adults and juveniles of the species. 4 At least two chemical cues dissolved in the water help to guide them. 5
In the aquarium
From the experience of the BallingMania community.
They live in all zones of the coral reef, from the innermost areas to the lagoons, swimming in groups to defend their territory.
It is strongly recommended to introduce the whole group of Chromis you wish to keep at the same time, to avoid acclimatisation problems for the last arrival, which could be constantly attacked by the specimens already in the tank.
The body of this fish is characterised by a pale blue livery that sometimes takes on emerald green tones. The mouth is not very prominent and the body is slender, with two medium-sized dorsal fins.
It is advisable to keep this fish in small schools of about 5/7 individuals in tanks of about 100/150 litres.
In the wild Chromis feed on small crustaceans, plankton and amphipods. To help these Pomacentridae settle in quickly, frozen food (Artemia, Cyclops and Mysis) is recommended; after this phase the fish can be fed flake and/or granular dry food, which they will accept willingly and eagerly. Breeding is possible in captivity.
photo by: Ciro Murino
What studies say about keeping it
Data from aquaculture and health-screening studies, not advice for a home aquarium. In a three-month coral culture trial, keeping corals with schools of juvenile C. viridis, or giving them water from the fish tank, generally increased the protein content or the density of symbiotic algae in the coral tissue, with differences between species. 14 In specimens imported into Brazil, in quarantine or at a wholesaler, infections by a protozoan of the genus Uronema were found, with bleeding and ulcers on the skin. 18 In a study on adaptation to less salty water, the fish kept their parameters within limits even at a salinity of 20‰, but activated stress responses in the gills. 19
Did you know?
Sources
- Froese R., Pauly D. (FishBase) (2026). Chromis viridis (Cuvier, 1830). World Register of Marine Species.
- Froese R., Pauly D. (eds.) (2026). Chromis viridis, Blue green damselfish. FishBase.
- Reef Life Survey (2026). Chromis viridis - Green puller. Reef Life Survey.
- Ben-Tzvi O., Abelson A., Polak O., Kiflawi M. (2008). Habitat selection and the colonization of new territories by Chromis viridis. Journal of Fish Biology.
- Ben-Tzvi O., Tchernov D., Kiflawi M. (2010). Role of coral-derived chemical cues in microhabitat selection by settling Chromis viridis. Marine Ecology Progress Series.
- Leray M., Alldredge A.L., Yang J.Y. et al. (2019). Dietary partitioning promotes the coexistence of planktivorous species on coral reefs. Molecular Ecology.
- Khalaf M.A., Abdallah M. (2014). Spatial distribution of fifty ornamental fish species on coral reefs in the Red Sea and Gulf of Aden. ZooKeys.
- Nanami A. (2025). Broad-scale spatial distribution, microhabitat association and habitat partitioning of damselfishes (family Pomacentridae) on an Okinawan coral reef. PeerJ.
- Ponton D., Loiseau N., Chabanet P. (2012). Does light explain damselfish Chromis viridis abundances observed over coral colonies?. Journal of Fish Biology.
- Nadler L.E., Killen S.S., McClure E.C., Munday P.L., McCormick M.I. (2016). Shoaling reduces metabolic rate in a gregarious coral reef fish species. Journal of Experimental Biology.
- Nadler L.E., Killen S.S., Domenici P., McCormick M.I. (2018). Role of water flow regime in the swimming behaviour and escape performance of a schooling fish. Biology Open.
- Rhyne A.L., Tlusty M.F., Schofield P.J., Kaufman L., Morris J.A., Bruckner A.W. (2012). Revealing the Appetite of the Marine Aquarium Fish Trade: The Volume and Biodiversity of Fish Imported into the United States. PLoS ONE.
- Biondo M.V., Burki R.P., Aguayo F., Calado R. (2024). An Updated Review of the Marine Ornamental Fish Trade in the European Union. Animals.
- Neil R.C., Barton J.A., Heyward A. et al. (2025). Improving Coral Grow-Out Through an Integrated Aquaculture Approach. Aquaculture Nutrition.
- GBIF Secretariat (2026). Chromis viridis, IUCN Red List category. GBIF.
- UNEP-WCMC (2026). Search for Chromis viridis in the CITES lists. Species+.
- Liu S.Y.V., Tuanmu M.N., Rachmawati R., Mahardika G.N., Barber P.H. (2019). Integrating phylogeographic and ecological niche approaches to delimitating cryptic lineages in the blue-green damselfish (Chromis viridis). PeerJ.
- Cardoso P.H.M., Moreno L.Z., Moreno A.M. et al. (2020). Scuticociliatosis caused by Uronema sp. in ten different ornamental aquarium reef fish in Brazil. Revista Brasileira de Parasitologia Veterinária.
- Tang C.H., Leu M.Y., Yang W.K., Tsai S.C. (2014). Exploration of the mechanisms of protein quality control and osmoregulation in gills of Chromis viridis in response to reduced salinity. Fish Physiology and Biochemistry.
- GBIF Secretariat (da Catalogue of Life) (2026). Chromis viridis, nomi comuni. GBIF.
Sources checked on 4 November 2026. Community texts and ratings are kept separate from the scientific data.