Green Chromis

Green Chromis

The Green Chromis is a relatively new saltwater fish that makes a great addition to many aquariums. They are so named because of the bright green body and orange-red bars on the bottom of their bodies. The colorations may vary slightly, but the basic coloring will always be green and orange. These are some of the most durable saltwater fish you can buy, and they will thrive for years in nearly any saltwater aquarium.

For most people their first impression of the Green Chromis is that it is a beautiful fish, as they are easy to identify by their brilliant yellow-green or blue-green color and bright blue eyes. A Green Chromis will remain colorful and active if you keep it in an aquarium that is properly cycled. (The fact that Green Chromis can illuminate an aquarium is a big bonus.)  Green Chromis are an excellent scavenger and will help keep your aquarium clean. 

The Green Chromis, also known as the Blue Green Chromis, is a member of the Damselfish family and are very popular with both beginner and experienced hobbyists. Unlike others in the family, this fish is known for its playful yet calm nature. They love to swim, play, and hide in and around coral formations and other decorations. 

Their sociability makes them ideal for community living. It is recommended to keep a large group of Green Chromis in a tank that contains other fish to prevent bullying.

Information about Green Chromis

  • Average size: 3 – 4 inches
  • Colors: Blue, green
  • Good Pet: Yes
  • Good with Other Green Chromis: Yes
  • Good with Other fish species: Yes
  • Suitable for First-Time fish Owners: Yes
  • Health Concerns: Marine Velvet and Marine Ich diseases are common 
  • Average Life Span: 8 to 15 years

Physical Appearance of Green Chromis

The fish has a pale blue to light green colors on the body and a distinct fork shaped tail. The fish is also known for having an oval body with the largest fish growing to about 4 inches. The males are also known to turn into a bright yellow color during mating as a way to attract the females.

Temperament of Green Chromis

The fish is a fast swimmer that occupies the middle to top column of the aquarium. Unlike other fish in the Damsel family that are aggressive, the Green Chromis is very shy and peaceful.

Tank Conditions

The fish enjoy swimming from the middle part of the aquarium. They really enjoy swimming among corals, rocks, and caves. These natural features are the best way to provide the perfect habitat for your fish. A 30 gallon tank should be the minimum tank size for the fish to have enough space to swim. If you want to have a school of Green Chromis consisting of 5 to 6 fish, then a 60 gallon tank would be better.

Green Chromis
Green Chromis

Filtration and Lighting

Filtration is an important aspect in your fish tank because it helps in cleaning and maintaining water quality. Green Chromis fish isn’t a messy fish, so you shouldn’t require a sophisticated filtration system. 

The lighting in the aquarium should be dim to mimic the natural habitat of the fish.


Because these fish are fairly timid, they enjoy hiding in caves and rocks. Be sure to place plenty of smooth rocks that cannot hurt your fish in the tank. Also try to have hollow caves for your fish to hide whenever it feels threatened. Lack of these hiding materials could stress your fish. Stressed fish have a lower tolerance to diseases making them susceptible to fish illnesses.

The bottom of the tank should have some sand or gravel substrate where your fish can rest. Green Chromis just like other saltwater fish enjoy resting on substrates when they get tired of swimming.

Water requirements

Water quality is the most important consideration to taking care of healthy and happy fish. The water temperature in the tank should range from 72.0  -82.0°F. It is also important that the pH in the aquarium remains between 8.1 and 8.4. You can quickly and easily test the pH using water testing kits.

The Attention requirements for Green Chromis

Green Chromis have very low attention needs.  They are resistant to most illnesses that other fish are susceptible to.  As long as they remain in a tank with good water conditions there is very little that needs to be done except to feed them.  This is why they are such a popular fish in many aquariums.

Tank Maintenance

Water changes

Every two weeks about 15 percent of the water in the tank should be changed out. The changes should ensure that water quality remains good for the health of your fish.

Health Issues

The Green Chromis are generally resistant to most saltwater fish diseases but can get sick if subjected to poor water and poor diet. Green Chromis can also become ill if placed together with aggressive tank mates that may induce stress. Here are some of the illnesses to watch out for if you have some Green Chromis.

Green Chromis
Green Chromis

Marine Velvet Disease

This disease is caused by a parasite called Amyloodinium in marine fish. A sick Green Chromis tends to move about in the tank scratching against obstacles in a bid to relieve the discomfort. As the disease progresses, the fish develops a goldish to brown looking dust on its body. In advanced stages of the illness, a sick fish has difficulties breathing, and the fins clamp together.

The illness can be treated using sea salt or copper but in doses your vet will recommend. Your vet is needed because an overdose of copper is dangerous to fish. The best tactic to dealing with this illness is removing all lighting options in the tank which disrupts the life cycle of the parasite as it thrives in light.

Marine Ich

Also known as Marine White Spot Disease, the illness is caused by a parasite called Cryptocaryon irritans. The illness is caused by poor water quality in the fish tank and manifests itself in the following ways.

  • White spots on the fish
  • Scratching against objects
  • Lethargy
  • Difficulties breathing
  • Weight loss due to lack of appetite

Unlike Freshwater White Spot Disease, the marine one doesn’t get eliminated by raising the water temperatures in the tank. Copper has been known to treat the illness as long as you consult a vet to guide on the quantities. The disease spreads rapidly and putting the sick fish in quarantine could help you protect the rest of the fish in the tank.

Best Tank Mates for Green Chromis

These fish are very peaceful and can live with any other peaceful fish. If you plan on introducing a mildly aggressive fish into the tank, your Chromis should be placed first to prevent territory wars.

Green Chromis also live well with coral and can be kept in a coral reef tank or a fish only tank. Here are some of the best tank mates for your pet.

Green Chromis
fish flakes

Feeding Green Chromis

Green Chromis are omnivorous and can eat vegetables and meaty foods. It’s recommended that the meat foods are given in larger quantities than the vegetables. Here are some of the best foods for your pet.

  • Algae
  • Fish flakes
  • Fish pellets
  • Mysis Shrimp
  • Fish eggs
  • Zooplankton
  • Phytoplankton
  • Shredded vegetables

The fish should be fed 2 to 3 times in a day being careful not to overfeed your fish. Leftover foods usually contaminate the fish tank leading to deterioration of the water quality. Poor quality can affect the health of your fish.

It’s also advisable to soak the foods in vitamin supplements to boost the health of your fish. The vitamins give your fish a more vibrant color.

Related Questions:

Is it possible to breed Green Chromis?

Green Chromis have been bred in aquariums but it requires having tanks that don’t have predatory fish that can eat the eggs and the small fries once hatched. The fish spawns every two weeks and the males display bright yellow colors during the mating period. You will find eggs about 4 days after spawning mostly found on the sides of the aquarium near the surface.

If you plan on raising fries to adulthood, consider having a separate tank for the eggs to hatch. This will allow the fries to grow to a big size such that they don’t get eaten by bigger fish in the main tank.

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