Blue-green chromis
Chromis viridis
Blue-green chromis (Chromis viridis) is a marine species with an adult-size reference of about 10 cm. It needs at least 250 litres and 5 individuals, with its social and territorial profile taken into account.
Water Temperature
24 - 28 °C
pH Value
8.1 - 8.4
Water type
Marine
Tank level
All levels
Adult size
10 cm
Minimum tank volume
>= 250 L
Minimum group
>= 5
Species description
Geographical Origin and Habitat: A marine species; the enclosure should provide stability, oxygenation, space and shelter consistent with its behaviour without turning one habitat description into a mandatory recipe.
Taxonomy and Morphology: The accepted scientific name is Chromis viridis; the verified classification records genus Chromis, family Pomacentridae, subfamily Chrominae, order Perciformes. Historical names remain searchable as synonyms rather than separate species.
Social Behavior: Blue-green chromis is gregarious and should be kept in a school. The minimum reference is 5 individuals; sex, maturity and available space can require a more conservative composition. Observe access to food, resting behaviour, chasing and use of shelter. Isolation, persistent competition or aggression means the number, composition or environment needs to be corrected.
Coloration and Sexual Dimorphism: Colour and shape can vary with age, sex, physiological state and environmental conditions. Identification and sexing require recognized species-level characters; one appearance or photograph is not enough.
Care, breeding and tankmates
Aquarium Setup: Blue-green chromis needs an aquarium of at least 250 litres, sized for adult body size and a minimum group of 5 individuals. Filtration, shelter and swimming room must match the species and the actual number kept. Volume alone does not make an enclosure suitable: tank shape and length, usable area, oxygenation and the ability to separate territories must reflect adult behaviour.
Diet and Feeding: The recorded diet is omnivorous. Offer appropriately sized foods varied within that category, and adjust quantity and frequency from actual intake, body condition and leftovers. One food or a fixed schedule is not suitable for every age and situation.
Water Quality: Maintain stable, well-oxygenated water appropriate to a marine species; the card's reference values are 24–28 °C, pH 8.1–8.4. Verify conditions with reliable tests and size maintenance and filtration to the actual load. Ranges are not automatic thresholds for treatment or rapid chemical correction.
Compatibility and Cohabitation: The cohabitation profile is reef-safe, with a generally active temperament. Keep at least 5 individuals; tankmates, stocking density and decor must allow escape, rest and feeding without excessive competition. Watch interactions especially during feeding, maturity and breeding. Persistent chasing, injury or exclusion from food requires a change in stocking or layout, or separation of the animals.
Aquarium Breeding: The recorded reproductive profile is “oviparity”. Breeding should be attempted only with healthy adults, separation capacity and a plan for eggs or young. Do not treat unverified triggers, sex ratios or hatch times as universal for this species.
Risks and Diseases: Prevent problems through quarantine of new arrivals, stable water, appropriate feeding and daily observation. Similar signs can have different causes, so check parameters, history and diagnosis before medication. Follow the product label and qualified aquatic-veterinary advice; there is no universal reduced dose for a species or family.
Geographic origin and distribution
A marine species; the enclosure should provide stability, oxygenation, space and shelter consistent with its behaviour without turning one habitat description into a mandatory recipe.
Origin
Africa and Madagascar
Fish profile
- Temperament
- Active
- Blue-green chromis has a generally active temperament. Insufficient space, an unsuitable social ratio or incompatible tankmates can substantially change observed behaviour.
- Diet
- Omnivore
- They are omnivorous and readily accept a massive variety of aquarium foods. A staple of high-quality marine flakes mixed with frozen mysis and cyclops is ideal. Frequent feedings of small planktonic foods will keep their pastel green color glowing.
- Life expectancy
- 5-15 years
- Adult size
- 10 cm
- Sex ratio
- School
- Blue-green chromis is gregarious and should be kept in a school. The reference minimum is 5 individuals and must not be read as permission to overcrowd the aquarium.
- Feeding frequency
- Twice daily
- For optimal health, feed them very small amounts three to four times daily. This constant access to food replicates their wild plankton-picking habits. Infrequent feeding can lead to wasting and heightened aggression within the school.
- Bioload
- Medium
- The Green Chromis is a small fish that introduces a very low bioload individually. When kept in the recommended schools, robust filtration and skimming are necessary. Maintaining excellent water conditions ensures they stay resistant to common diseases.
- Flow
- Strong
- They deeply appreciate strong, varied flow across the top of the aquarium. High flow environments stimulate their natural schooling instincts and keep them active. A well-circulated tank also ensures higher oxygenation, which they require.
- Jump risk
- No
- Reproduction
- Oviparous
- They are demersal spawners that occasionally breed on the aquarium glass or rocks. The male turns a yellowish color and vigorously fans the eggs to prevent fungus. Rearing the fry requires green water and rotifers, making it a very difficult task.
- Compatibility & tankmates
- Reef safe
- The cohabitation profile is reef-safe, with a generally active temperament. Keep at least 5 individuals; tankmates, stocking density and decor must allow escape, rest and feeding without excessive competition. Watch interactions especially during feeding, maturity and breeding. Persistent chasing, injury or exclusion from food requires a change in stocking or layout, or separation of the animals.
- Tank level
- All levels
- Green Chromis spend the vast majority of their time in the upper water column. They enthusiastically swim against the current in the open spaces above the reef. During the night, they dive deep into the rockwork to sleep securely.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
FishBase Catalog curation 2026-05-09Data synced on: 06/15/2026
- Trophic level
- 2.9 ± 0.1 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5
- Bayesian Length-Weight
- a = 0.02042, b = 2.9
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
