I think one of my green chromis is Chromis atripectoralis

[Justiful]

I bought 3 green chromis. 2 are small... one is quite large. The two small ones try and school with him... but he tends to chase them more than school. Especially during feeding.

Does anyone have a picture of Chromis atripectoralis ... I know a small black dot under pectoral fin, but how small are we talking?

 

[KJ]

Black Axil Chromis (Chromis atripectoralis)

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QUICK STATS
Minimum Tank Size: 30 gallons
[URL='https://www.reef2reef.com/javascriptopupWindow('/product/refinement_definition.cfm?rid=2', 50, 50, 450, 400, 'scrollbars')']Care Level: Easy
Temperament: Peaceful
Reef Compatible: Yes
Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
Max. Size: 4½"
Color Form: Black, Blue, Green
Diet: Omnivore
Compatibility: View Chart
Origin: Fiji
Family: Pomacentridae

What do these Quick Stats mean? Click here

overview
The Black Axil Chromis is easy to care for, beautiful, and peaceful. This member of the Pomacentridae family is most recognizable by its gorgeous light aqua dorsal side that slowly fades into a majestic iridescent green belly. Lacking the black blotch at the base of the pectoral fin the juvenile Black Axil chromis are often confused with the Chromis viridis. Once the Black Axil Chromis begins to mature the black blotch will appear. The Black Axil Chromis is desirable not only for its beauty, but also for its peaceful demeanor (despite its designation as a true damselfish) and ability to be kept with almost all other community fish, invertebrates, and corals.
Native to reefs ranging from mid-depth to shallow lagoons of the Indo-Pacific and South Pacific, wild specimens prefer to school in large shoals amongst branching corals like Acropora. In the home aquarium, the Black Axil Chromis does best in similar environments and will actively swim at all levels of the aquarium water column. In fact, small schools of the Black Axil Chromis add a dazzling and dramatic shimmer of beauty to almost any larger, well-established reef system.
Overall, the Black Axil Chromis is very hardy and can live between 8 to 15 years in aquariums with excellent water quality. For best care, feed several times throughout the day with a varied diet of meaty foods, herbivore flakes, and frozen preparations. Vitamin-enriched foods may also help to preserve body colorations.
Some aquarists have successfully bred the Black Axil Chromis in the home aquarium. Interestingly, the body color of mature males, ready to nest, changes to a muted yellow color. However, breeding success requires perfect water parameters in only the largest of non-predatory aquarium systems.
Approximate Purchase Size: Medium: 1-3/4" to 2-1/2"; Large: 2-1/2" to 3-1/2"




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[4FordFamily]

Honestly larger chromis look different from smaller chromis (larger often more colorful).

Chromis are aggressive towards other chromis of their own size, a school will often be reduced to one or very few in time. Add in a large size differential and it's especially true.

 

[eatbreakfast]

Whenit flaps it's pectoral fins down the black spot is visible, when the pectoral fins are against the body it is not visible. Other than that atripectoralis and viridis are nearly identical.