Blue-green chromis

Chromis atripectoralis

Also known as Black-axil Chromis, Blackaxil Chromis, Blue-green Puller

SaltwaterFish

Care at a glance

Temperature
75–82°F
24–28°C
pH
8.1–8.4
Adult size
4.7 in
12 cm
Minimum tank
30 gal
115 L
Temperament
Peaceful
Social behavior
Schooling
Swim level
Middle
Difficulty
Easy
Breeding
Hard
Rarity
Common
Reef safe
Reef safe
Family
Pomacentridae
Origin
Indo-Pacific

Overview

A peaceful, hardy schooling fish that behaves much like the green chromis and is easy to confuse with it in stores. Keep it in a group of six or more so aggression stays diffused across the shoal, since small groups tend to develop a pecking order that thins the group over time. It ignores corals and inverts and eats frozen and prepared foods eagerly, making it a solid community reef fish.

In the wild

Lives in shoals over branching corals in lagoons and on protected reef slopes across the Indo-Pacific, in the same habitats as the very similar green chromis. Groups hover above the coral picking plankton from the current and dive into the branches for cover when threatened.

Good to know

Chromis atripectoralis is nearly identical to Chromis viridis but grows a little larger and carries a small dark blotch at the base of the pectoral fin, which gives it the name black-axil chromis. Like its relative it is a plankton-feeding damselfish whose males guard demersal eggs, and its larvae drift in open water.

Did you know

The easiest way to tell it apart from the near-identical green chromis is the small black spot tucked into the armpit where the pectoral fin meets the body.

Weekly picks

Tank mates

Blue-green chromis is a peaceful, schooling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a Blue-green chromis need?

A Blue-green chromis needs at least 30 gal (115 L). It spends most of its time in the middle.

What temperature and pH does a Blue-green chromis need?

A Blue-green chromis is comfortable at 75–82°F (24–28°C) with a pH of 8.1–8.4.

How big does a Blue-green chromis get?

An adult Blue-green chromis reaches about 4.7 in (12 cm).

Does a Blue-green chromis need a group?

Yes. A Blue-green chromis is a schooling species and should be kept in a group, not singly.

Related species