OtterAquatics is reader-supported. When you purchase something through an outgoing link, we might earn an affiliate commission.

Care Guide: Green Chromis

Table of Contents

Green Chromis are known as some of the most effortless and most hardy fish to keep in a saltwater tank.

They are a favorite beginner saltwater fish among reef tank owners because they are among the most affordable fish to introduce to an aquarium and are of a peaceful temperament.

  • Scientific Name: Chromis viridis
  • Care Level: Easy
  • Minimum Tank Size: 20 gallons
  • Diet: Omnivore
  • Temperament: Peaceful
Green Chromis

What do they look like?

Green chromis are small, pale greenish-blue fish. They are easy to spot both in the wild or in captivity because of their shimmery exterior, giving them a unique look compared to other basic saltwater fish.

Their dorsal fin stretches from the front of their head to their tail, spanning almost the entire length of their body. This helps them to be able to navigate quickly through the water as they search for food.

Watching the growth process of a green chromis is fascinating. If you purchase a baby one, it will be tiny. However, these fish grow rapidly. They can get up to 3” in length within months, growing even larger to 4” in their natural habitat. This is something to consider if you plan on adding other fish at the same time.

What is their natural environment like?

These fish can be found in the Indo-Pacific region of the world, meaning they populate areas from the Philippines all the way to Hawaii.

They prefer shallow water to deeper parts of the ocean, so they will more than likely live in water areas with low flow and plenty of other fish.

Their natural habitat is often near a reef, causing them to love to search through coral for food.

Green chromis can live up to 15 years old, with the average lifespan being eight years. Therefore, these fish can be residents of your tank for years if you take proper care of them.

What size tank do they belong in?

To give your green chromis the best environment possible, you need to keep them in the right size tank. They can be kept in as small as 20 gallons, making them perfect for tank owners looking to have a smaller-sized aquarium.

Although green chromis are highly versatile fish, meaning they can survive in a variety of different environments, there are a few stipulations you should consider when putting one in your tank:
Give them plenty of room to swim. 

Green chromis are a schooling type of fish, meaning they are more likely to be found with a large group of like fish than alone. It’s essential to keep this in mind when adding green chromis to your tank, as they’re much happier when they are swimming with others. 

They develop their social skills by swimming in schools, keeping them happy and healthy. However, be mindful of how many green chromis you introduce at one time. If the school is too big for your tank, it can cause massive waste buildup – which can be detrimental to the health of your fish. 

Six to seven is the recommended number.

Provide them with lots of coral to navigate through. Hard coral, also known as SPS coral, makes the best addition to your tank.

Incorporate as much live rock as possible. If you’re a new aquarium owner, you’ve probably spent hours finding the perfect aquascape for your tank. 

This is one of the most important parts of setting up a tank, as it will set the stage for where your fish can find food, interact with other fish, and find hiding places. 

Green chromis love to eat off of the live rock, so this is where you will find them most of the time.

What is their temperament?

Green chromis are easy-going, laid-back fish. They will be reasonably active in your tank, so don’t be surprised if you see them darting from one rock to another to search for food.

Their temperament is drastically different from other fish in the damselfish group, which are often known for being extremely aggressive with their own kind and other species of fish. 

For some reason, green chromis are notoriously friendly towards other fish in the tank like gobies or clownfish, but can get slightly aggressive with other chromis in their school as they determine their hierarchy among themselves.

What do they eat?

Green chromis are omnivores.

This means they can have meat and plant-based diets.

Because they are such hardy fish, green chromis also rely on a versatile diet to keep them healthy.

They eat on small microorganisms within your tank like mysis shrimp, copepods, and algae growing on live rocks.

You can also feed them fish flakes or pellets.

Green Chromis Breeding Guide

Green Chromis have been successfully bred in captivity, and are egg spawners.

Once they feel they are in a safe environment, and breeding season comes along, a bonded male and female(s) will begin the breeding process.

Just like all fish – the egg laying process is not the hard part.

It’s raising the fry.

Considering eggs and fry typically make great fish food, it’s recommended that you somehow separate the newly laid eggs from the other tank mates. Whether that be by removing the eggs, or the other fish.

Successfully rearing the fry will require a combination of rotifers, brine shrimp, and high end flake food. This process is out of the scope of this article but something we want to cover in the future.

Let us know in the comments if you’d like to see a tutorial!


Ready to put a green chromis in your tank?

As you can tell, green chromis are fish that are easy to take care of if given the proper environment. They are not a fish that will overwhelm your tank or your time, making them perfect for beginners. If you are interested in learning more about other saltwater fish to add to your aquarium, check out our other articles.
  • Welcome

    My name’s Austin, and I created OtterAquatics to teach aquarists of all skill levels on how to succeed in the hobby.