Chromis viridis (Blue Green Chromis fish)

Chromis viridis

Chromis viridis, also known as the blue green chromis fish, blue chromis fish, blue-green damselfish, blue green reef chromis, blue puller, or just blue chromis, is one of the most popular saltwater aquarium fish.

They are very active swimmers and are recommended to be kept in schools of 10 or more (if possible). Chromis viridis prefer water temperatures between 77 and 84 degrees Fahrenheit, with pH levels from 8.1 to 8.4 (slightly acidic).

The Blue Green Chromis fish are vibrant and popular tropical fish to keep in an aquarium, either as part of a larger community tank or as individuals in their own tank if there are no other inhabitants that will harass them. They have beautiful blue-green colored scales and are extremely easy to care for, making them great fish to keep even for beginners.

Chromis viridis is an omnivorous marine tropical saltwater fish found in shallow waters throughout the Indo-Pacific and the Red Sea. They were named by Risso in 1826 from the Greek word chromas meaning color and refer to their vibrant blue coloration and iridescent green scales. This brightly colored fish has a white belly with its elongated body tapering into its distinctive forked tail fin.

Origin and description

Chromis viridis is a small, colorful saltwater fish. It is most commonly found in the shallow waters of the red sea and the Indian Ocean but can be found all over the world. They are known for their bright colors and relative docility compared to other saltwater species. They are also relatively inexpensive, making them an appealing choice to new hobbyists.

Though they are generally quite peaceful creatures, they will fight when it comes time to choose a mate or stake out territory during spawning season. When you’re shopping for your first Chromis viridis, it’s best to find one that is already paired up with another so they have a fighting chance at finding happiness together in your home aquarium!

Species profile

Chromis viridis

The blue green Chromis is a very popular aquarium fish and is often kept in saltwater tanks. They are considered reef safe, but they need lots of hiding places to feel safe and comfortable. A typical tank will have large live rocks or corals with lots of nooks and crannies that the Chromis viridis can hide in during the day.

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Common names of Chromis viridis

Common names of Chromis viridis are blue green chromis fish, blue-green damselfish, blue chromis fish, blue green blue puller, blue chromis, or reef chromis.

Chromis viridis habitat

The Chromis viridis is a reef-associated, non-migratory, marine fish. This species lives in coral and rocky reefs in the tropical Indian and Pacific Oceans. They are reef-dwelling, nocturnal, and solitary, hiding during the day in coral caves or under ledges.

During night hours they forage for food, typically algae or small crustaceans. The color of the chromis’ body changes with age; juveniles have yellow-green bodies while adults develop a striking iridescent blue sheen to their scales.

Blue chromis size

The Blue Green Chromis is a small, slender fish that can grow up to 4 inches (10 cm) in length.

Chromis viridis tank size

Chromis viridis do best in tanks that are at least 30 gallons (114 liters) in size. If keeping a school of 6, provide at least 55 gallons, and then increase the size of the tank if there are more fish.

Tank mates

They often do well in community aquariums with semi-aggressive fish like more peaceful tangs, but they should not be kept with aggressive anthias or pygmy angelfish. Semi-aggressive fish, even the largest, do well in large tanks with less aggressive fish.

The Niger Trigger is an example of a relatively mellow triggerfish, whereas more aggressive triggerfish will attack the Blue Green Chromis. Tangs and surgeonfish are no different.
Basslets, Blennies, and Butterflies are all friendly community fish you can keep with them.

Keep them away from aggressive fish of any size and larger fish that might swallow them whole. When a Chromis stays near the upper corner of a tank, it is a sign that it is being bullied. Depending on your preference, you can remove either the bully or the Chromis.

Green chromis breeding

Chromis viridis

It is sometimes possible to breed Blue Green Chromis in captivity if the aquarium conditions are right and the fry and eggs are kept safe. If you want to ensure the survival of your offspring, you should separate the breeding pair and place them in a separate breeding tank.

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Separate aquariums can also be used to control temperature and light levels, both of which are crucial factors for stimulating fish to breed.

To breed successfully, it is essential to have perfect water parameters and a large aquarium system that does not contain predators. It is believed that all Chromis species spawn at an optimal temperature of 79°F to 83°F (26°C to 28°C), which is the same temperature for clownfish.

A large number of eggs are laid by more than one female blue green chromis in a nest prepared by the males in the sand bed. The male fertilizes the eggs externally by spraying his sperm on them. In a couple of two to three days, depending on the water temperature, they will tend to the nest and protect the eggs until they hatch. Usually, males eat eggs that are unfertilized or that do not hatch.

In order to prevent Chromis adults from eating their young after hatching, remove the adults once the eggs have hatched. It is important for blue green chromis juveniles to consume high-fat and high-protein diets in order to ensure proper development.

Are they aggressive or peaceful?

The Chromis viridis are not aggressive and can be kept in a community aquarium. They should be housed with other peaceful, non-aggressive fish that live in mid-level temperatures. They are also reef safe and will feed from the surface as well as on the bottom of the tank.

Chromis viridis care information

Chromis viridis

The Blue-Green Chromis is a small, colorful saltwater fish that is an excellent choice for the beginning marine aquarium hobbyist. They are very hardy and are considered one of the easiest saltwater fish to keep in captivity. However, they do need regular maintenance because they will eventually excrete ammonia into their environment.

Chromis viridis diet

The blue green chromis is a hardy, omnivorous saltwater fish that enjoys a variety of food sources. These include brine shrimp, small silversides, invertebrates such as crabs and mussels, and plant matter like algae and seaweed. The blue green chromis is also very fond of live foods including small shrimp and cut pieces of squid.

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Tank requirements

To keep a chromis in your tank, you need to have a tank that is at least 30 gallons (114 liters) of water. They also require live rock to survive, as they feed on the algae that are found on it. If you’re going to keep them with corals, make sure they’re tough species like acropora or pocillopora. These fish enjoy swimming around plants but will eat them too.

You’ll want to add more plants if this happens so they don’t end up eating all the ones you already have.

Your tank should be made out of glass so they don’t get injured trying to break out of something that isn’t see-through. The coloration varies from greenish blue, grayish brown, yellow-green, and even black on some occasions. It’s very hard to tell which coloration is male and which one is female.

The females tend to grow bigger than the males though.

Additionally, this species has a low tolerance for nitrate levels in the water. It is suggested that a maximum of 0.3 ppm be maintained in the aquarium or tank if a high population density is desired, as well as water quality should be monitored closely for pH changes which may require frequent partial water changes.


The lifespan of a Chromis viridis can range from 8 to 15 years.

Parasites and diseases

The Chromis viridis is prone to many diseases and parasites including protozoans, worms, ichthyopthirius multifilius (Ich), haemobartonellosis, and bacterial infections. Ich is the most common parasite that attacks the blue green chromis, and when left untreated it can lead to infection of the entire body.

A symptom that often occurs in infected individuals is white spots on the skin and gills. If you have a marine aquarium with this species then keep an eye out for any signs of illness or stress, which may be a sign of disease or parasitic infestation. Symptoms such as erratic swimming behavior, clamped fins, or loss of appetite are also possible indicators.

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Predators (What animals prey on them)

Predators are anything that will eat a blue green chromis. The predators of the blue green chromis include marine animals such as urchins, sea stars, and triggerfish. They also can be eaten by other fish such as the tiger shark. Human beings are also a predator to this species because they sometimes take them out of their natural habitat and use them for their own purposes.

Do they make good pets?

Chromis viridis, or Blue Green Chromis Fish, is reef compatible and can be a good pet.

They are easy to care for and don’t require a lot of attention. Since they are reef compatible they will eat any uneaten food that falls to the bottom of the tank as well as live plants in an aquarium. They should not be put with aggressive tank mates or with other chromis in order to avoid territorial disputes.