Common names for the Blue-Green Chromis include; Blue Chromis, Green Chromis & Schooling Chromis.

These busy and playful fish like to occupy the mid to upper portions of a tank, they can be kept in schools, but you will likely find if you put more than 3 in, you will end up with 3 in the end. When in schools they will likely pick on and kill the weakest member of the shoal, until you reach just 3 of them. 3 is definitely the magic number with these fish (according to many experienced reef keepers).

They are popular fish within the hobby due to their generally peaceful nature & affordability. Most Damsels are known for being tank terrors, but these guys tend to just keep to themselves.

Tank Requirements & Facts

Blue-Green Chromis
Blue-Green Chromis
  • Family: Damsel
  • Minimum tank size: 30 Gallon (136 Litres)
  • Prone to disease: No
  • Beginner Compatible: Yes
  • Adult Size: 4 inches (10cm)
  • Reef Compatible: Yes
  • Predator Tank Compatible: No
  • Care Level: Easy
  • pH: 8.1 to 8.4
  • Temperature: 22°C to 27°C
  • Preferred Tank Level: Mid to upper region, but they appreciate additional hiding spaces
  • Number to a tank: Can be kept in shoals or singularly, but 3 seems to be the magic number.


  • These are omnivores
  • They catch their food in the water column as it passes them
  • They don’t tend to graze on Nori
  • Flaked food, pellets, frozen food & live foods are readily accepted


When acclimating your Chromis it is best to do so in a deep bucket that the fish is unable to jump out of.

Place your fish in the bucket and then drip acclimate for about 45 minutes at a rate of 3 drips per second. This should bring the fishes water parameters in line with your tanks parameters.

Once your fish has been drip acclimated, catch the fish with a net and place it gently into your tank. Do not put any of the water the fish originally came in, into your tank.

Care should be taken after adding the fish to ensure there is a tightly fitting lid on the aquarium at all times. These fish are known to be jumpers and they are more likely to jump when first introduced to an aquarium.

Why are Blue-Green Chromis so popular?

Pair of Blue-Green Chromis
Pair of Blue-Green Chromis

The Blue-Green Chomis is popular with a broad spectrum of aquarists for the following, simple reason;

  • They add a splash of blue-green tank which is not an overly common colour in saltwater fish.
  • They are one of the most affordable saltwater fish available on the market. You can expect to pay just £7.00 to £15.00 per fish.
  • They are easy to keep. They can tolerate slight parameter swings, they are not fussy with the food they eat & they can be kept in shoals without any real problems.
  • They are reef safe.
  • They are friendly towards other fish species, they won’t try to bully your prized Tang!
  • They are very active & not overly shy, so you will get to see them in your aquarium.

Overall, the Blue-Green Chromis is a great addition to most tanks!


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