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.

Fire shrimp
Lysmata debelius
Saltwater2.4 in (6 cm) · 20 gal (75 L)72–79°F (22–26°C)
Ring cowrie
Monetaria annulus
Saltwater1.2 in (3 cm) · 20 gal (75 L)75–81°F (24–27°C)
Gold-specs jawfish
Opistognathus randalli
Saltwater3.9 in (10 cm) · 30 gal (115 L)73–81°F (23–27°C)
Golden basslet
Gramma dejongi
Saltwater2.8 in (7 cm) · 29 gal (110 L)75–81°F (24–27°C)
Camel / dancing shrimp
Rhynchocinetes durbanensis
Saltwater2 in (5 cm) · 16 gal (60 L)75–81°F (24–27°C)
Fighting conch
Strombus alatus
Saltwater3.1 in (8 cm) · 20 gal (75 L)75–81°F (24–27°C)
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
5.1 in (13 cm)53 gal (200 L)73–81°F (23–27°C)Blue chromis
Chromis cyanea
5.1 in (13 cm) · 53 gal (200 L)
3.1 in (8 cm)30 gal (115 L)75–82°F (24–28°C)Green chromis
Chromis viridis
3.1 in (8 cm) · 30 gal (115 L)
4.7 in (12 cm)30 gal (115 L)75–82°F (24–28°C)Cinnamon clownfish
Amphiprion melanopus
4.7 in (12 cm) · 30 gal (115 L)
4.7 in (12 cm)53 gal (200 L)75–81°F (24–27°C)Golden damselfish
Amblyglyphidodon aureus
4.7 in (12 cm) · 53 gal (200 L)
5.1 in (13 cm)40 gal (150 L)75–82°F (24–28°C)Saddleback clownfish
Amphiprion polymnus
5.1 in (13 cm) · 40 gal (150 L)
4.3 in (11 cm)26 gal (100 L)75–82°F (24–28°C)Skunk clownfish
Amphiprion akallopisos
4.3 in (11 cm) · 26 gal (100 L)
