Blue Green Damsel (Chromis viridis) 2.5-5 cm

Overview

The Blue Green Damsel, Chromis viridis, is one of the most popular marine aquarium fish for good reason: it is attractive, hardy, active, and well suited to established saltwater systems. Also known simply as the Blue Green Chromis, this species displays a beautiful metallic blue-green sheen that catches the light as it moves through the water column. The 2.5-5 cm size offered here is ideal for aquarists looking to add a small, healthy juvenile to a reef or fish-only marine aquarium.

In nature, Blue Green Damsels are shoaling fish that spend much of their time in open water above branching corals. In the aquarium, they are best kept in groups where they can display their natural schooling behaviour. They are generally peaceful, though as with many damsels, individual temperament can vary and hierarchy may develop within a group. When provided with adequate space, rockwork, and a stable marine environment, they make excellent additions to community reef tanks.

At Tropical Fish Co, we aim to supply robust livestock with careful handling and prompt dispatch. This species is available with our live arrival guarantee and fast UK delivery, helping your fish arrive in the best possible condition for acclimation.

Care at a Glance

Origin & Natural Habitat

Chromis viridis is native to the tropical Indo-Pacific, including reef systems across the Indian Ocean and western Pacific. It is typically found around coral reefs, lagoon edges, and sheltered seaward slopes where branching corals provide both cover and a place to shoal. These habitats are warm, clear, well-oxygenated, and highly stable, with strong natural water movement and abundant planktonic food.

The species’ natural behaviour is closely tied to open-water reef life. Blue Green Damsels often hover above coral heads in loose groups, darting into cover when threatened. This reef-associated lifestyle is why they do best in aquariums with plenty of swimming space, live rock, and moderate flow rather than heavily cluttered tanks.

Tank Setup & Water Parameters

For best results, house Blue Green Damsels in a mature marine aquarium with stable salinity and excellent filtration. A minimum of 150 litres is suitable for a small group, but larger systems are strongly recommended, especially if you plan to keep multiple individuals or mix them with other active reef fish. Because they are shoaling fish, they are usually more confident and natural-looking when kept in a group of five or more, provided the tank is large enough to reduce bullying.

Provide plenty of open swimming space alongside rockwork that creates caves, ledges, and retreat areas. Live rock helps establish biological filtration and gives the fish places to settle at night. Moderate water movement is ideal, as it mirrors their reef environment and keeps oxygen levels high. A secure lid is recommended, as active marine fish can jump when startled.

Stable water quality is essential. Keep ammonia and nitrite at zero, and maintain low nitrate through regular water changes and efficient filtration. As with all marine livestock, avoid sudden changes in salinity, temperature, or pH. Acclimate slowly using a drip method when introducing new fish to reduce stress.

Feeding Guide

Blue Green Damsels are omnivores with a strong appetite, which makes them straightforward to feed in captivity. Offer a varied diet of quality marine flakes or pellets, supplemented with frozen foods such as mysis shrimp, enriched brine shrimp, copepods, and finely chopped marine meaty foods. They will also graze on small amounts of algae and biofilm, so a mixed diet is beneficial for long-term health and colour.

Feed small portions once or twice daily, only as much as the fish will consume within a few minutes. Variety is important: rotating foods helps support immune function, colouration, and overall vitality. Juveniles may feed more eagerly and benefit from smaller, more frequent meals. As with all marine fish, remove uneaten food promptly to protect water quality.

Tank Mates / Compatibility

Blue Green Damsels are generally more compatible than many other damselfish species, especially in larger aquariums. They can be kept with a wide range of peaceful to semi-peaceful reef-safe fish, including clownfish, gobies, blennies, cardinals, wrasses, and many tangs in appropriately sized systems. They are also usually suitable for coral reefs and mixed invertebrate setups, as they do not typically bother corals or ornamental shrimp.

That said, compatibility depends on tank size and stocking order. Introduce Blue Green Damsels after more timid fish have settled, or add them to a sufficiently spacious aquarium where territories are less likely to form. In smaller tanks, they may become assertive toward similar-shaped or similarly coloured fish, particularly other chromis or damsels. Keeping a group can help distribute aggression, but only if the aquarium is large enough to support the shoal.

Avoid housing them with highly aggressive species, very small shy fish that may be intimidated, or multiple damselfish species in cramped quarters. In nano tanks, their natural social behaviour can turn into chasing and stress. As a rule, the larger and more structured the aquarium, the better their temperament will be.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we understand that marine fish need careful sourcing, handling, and dispatch to arrive in top condition. Our Blue Green Damsels are selected for health, colour, and vitality, then packed with care for safe transit. We offer fast UK delivery and a live arrival guarantee for added peace of mind, so you can order with confidence.

Whether you are building your first reef aquarium or adding movement and colour to an established marine setup, Chromis viridis is a reliable and eye-catching choice. With the right tank conditions, a balanced diet, and sensible stocking, this species can thrive and bring constant activity to the upper levels of your aquarium for years to come.