Green Chromis

a close up of a Green Chromis swimming

Green Chromis are beautiful tropical fish that are known for their vibrant green appearance. They are native to the Indian Ocean and Pacific Ocean, and are commonly found in saltwater aquariums. They are very peaceful and easy to care for. They are also very hardy, and can withstand a wide range of temperatures.

Green Chromis are a relatively new saltwater fish, and they make a great addition to many family aquariums. They are named because of their bright green body and orange-red bars on the bottom of their body. Their coloration may vary slightly, but their 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 them 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. 

Green Chromis, also known as the Blue Green Chromis, is a member of the Damselfish family and is very popular with both beginner and experienced hobbyists. Unlike others in the family, they are known for their 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. We recommend keeping a large group of Green Chromis in a tank that contains other fish to prevent bullying.

Green Chromis Information

  • Average size: 3 – 4 inches
  • Colors: Blue, green
  • Good Pet: Yes
  • Tolerance to Heat and Cold: More cold than warm
  • Good with Other Green Chromis: Yes
  • Good with Other fish species: Yes
  • Good for Less Experienced Pet Owners: Yes
  • Health Concerns: Marine Velvet and Marine Ich
  • Average Life Span: 8 to 15 years

Physical Appearance of Green Chromis

several Green Chromis swimming and feeding next to the coral

Green Chromis have a pale blue to light green oval shaped body and will grow up to 4 inches long. They have a distinct fork shaped tail. The males are also known to change to a bright yellow during mating as a way to attract females.

Temperament of Green Chromis

Green Chromis are fast swimmers that occupy 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.

Best Tank Mates for Green Chromis

These fish are very peaceful and can live with any other non aggressive 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.

Tank Conditions

They enjoy swimming in the middle 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 size tank so that they have enough space to swim. If you want to have a school of 5 to 6 Green Chromis, then a 60 gallon tank would be better.

a close up of a Green Chromis swimming in a dark aquarium

Filtration and Lighting

Filtration is an important part of keeping your fish tank clean and maintaining the water quality. Green Chromis aren’t a messy fish, and you shouldn’t need an expensive or sophisticated filtration system.

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


These fish are fairly timid and they enjoy hiding in caves and rocks. Be sure to place plenty of smooth rocks that won’t hurt your fish. Try to have hollow caves for your fish to hide whenever it feels threatened. Lack of these hiding places can stress your fish. Stressed fish have a lower tolerance to diseases making them susceptible to fish illnesses.

The bottom of the tank should have a 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 part of keeping healthy and happy fish. The water temperature in the tank should be kept between 72.0 and 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.

Tank Maintenance

many Green Chromis swimming around some large coral

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.

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.

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.


Marine Uronema is a parasitic organism that can infect saltwater fish. It belongs to the group of flagellated protozoa and is often found in aquariums with poor water quality, overcrowding, and stressed fish.

The infection caused by Marine Uronema can be deadly if not treated promptly. Affected fish can have symptoms of lethargy, appetite loss, rapid breathing, and skin redness or inflammation. In severe cases, the fish can also develop ulcers or open sores.

Marine Uronema primarily attacks a fish’s gills and skin, causing damage to their respiratory system and weakening their immune system. A weakened immune system makes them more susceptible to other infections and diseases.

Marine Velvet Disease

Marine Velvet Disease, also known as Velvet Disease or Coral Fish Disease, is a parasitic infection that affects saltwater fish. It’s caused by the dinoflagellate called Amyloodinium ocellatum, which attaches itself to a fish’s skin, gills, and fins.

The first signs of Marine Velvet Disease are usually a yellowish-gold dusting or velvet-like film on the fish’s skin. As the infection progresses, affected fish can become lethargic, lose their appetite, and display rapid breathing or gasping for air. In severe cases, Marine Velvet Disease can be fatal.

Symptoms of Marine Velvet Disease

Symptoms of Marine Velvet Disease include:

  • Yellowish-gold dusting or velvet-like film on the fish’s skin
  • Lethargy
  • Appetite loss
  • Rapid breathing or gasping for air

In severe cases, affected fish can also develop open sores and have abnormal swimming behavior.

Marine Ich

Marine Ich, also known as White Spot Disease, is a common parasitic disease that affects saltwater fish. It’s caused by the ciliate protozoan parasite and Cryptocaryon irritans, which attach themselves to a fish’s skin and gills.

Marine Ich is very contagious and can spread quickly through an aquarium. It’s often introduced into an aquarium through new fish or contaminated equipment. Poor water quality and stress can also weaken a fish’s immune system, making them more susceptible to the disease.

Symptoms of Marine Ich

Symptoms of Marine Ich include:

  • White spots on the skin and fins of infected fish
  • Rubbing against objects in the aquarium

As the disease progresses, fish can become lethargic and lose their appetite.

Feeding Green Chromis

a large pile of colorful fish flakes

Green Chromis are omnivorous and can eat vegetables and meat. Their diet should include slightly more meat than vegetables. Here are some of the best foods for your fish.

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

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

It’s a good idea to soak their food in a vitamin supplement 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 will be a bright yellow 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. A separate tank will allow the fries to grow to a size where they won’t get eaten by bigger fish in the main tank.

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Maryna is an animal expert that has had dozens of animals in her life over the years. She has never found an animal that she didn't love immediately. It seems like every year she finds kittens that have been abandoned by their mom and she nurses them to health and finds homes for them. She contributes her vast knowledge about animals and family pets to our website and we're forever grateful to have her working with us. She's also an amazing graphics designer and has designed all of the social media images that we use across all platforms.