Green Chromis fish

Chromis fish (Chromis viridis)

Local Pickup only

 

Overview

The Chromis fish (Chromis viridis), often called the Blue/Green Chromis, is one of the most popular saltwater schooling fish for reef aquariums. Belonging to the damselfish family, Chromis are admired for their shimmering blue-green coloration, active schooling behavior, and peaceful nature compared to most other damselfish. Their constant mid-water swimming adds life and movement to reef tanks, making them a favorite for both beginners and experienced aquarists.

Chromis are hardy, adaptable, and thrive in groups, making them an ideal choice for aquarists who want to add both beauty and activity to their reef display.

 

Key Care Information

• Species: Chromis viridis (Blue/Green Chromis – most common)

• Common Names: Blue Chromis, Green Chromis, Blue/Green Chromis

• Size: 3–4 in (7–10 cm)

• Temperament: Peaceful (though mild aggression can occur within groups)

• Reef Safe: ✅ Yes – safe with corals and inverts

• Tank Size: 30+ gallons for a small group; larger tanks (75+ gallons) recommended for big schools

• Placement: Open swimming space in the mid to upper water column

 

Tank Requirements

• Aquascape: Plenty of open swimming space with rockwork for shelter

• Lighting: Standard reef lighting; coloration pops under blue actinics

• Water Flow: Moderate to strong, mimicking reef currents

• Water Parameters:

  • Temperature: 74–80°F (23–27°C)

  • Salinity: 1.023–1.025

  • pH: 8.1–8.4

  • dKH: 8–12

 

Diet & Feeding

Chromis are omnivorous planktivores in the wild, feeding on zooplankton and algae. In captivity, they accept a wide range of foods:

• Frozen mysis and brine shrimp

• High-quality marine flakes and pellets

• Enriched frozen plankton or copepods

• Occasional algae-based foods for balance

👉 Feed small amounts 2–3 times daily to support their active metabolism.

 

Behavior & Compatibility

• Best kept in groups of 5+ (schooling behavior is most visible in larger groups).

• Can show mild aggression within the group (establishing hierarchy), but generally peaceful.

• Compatible with nearly all peaceful reef fish, inverts, and corals.

• Avoid housing with very aggressive species (e.g., large triggers, aggressive damsels).

 

Breeding Notes

Chromis have been bred in captivity. Males prepare a nesting site, guard the eggs, and fan them until they hatch. While challenging to raise larvae, it is possible with specialized care.

 

✅ Fun Facts

• Unlike their more aggressive damselfish relatives, Chromis are known as the “gentle damsels” of the reef.

• In the wild, they form large, shimmering schools over coral heads, darting in and out for protection.

• Their color can shift between blue and green depending on lighting, mood, and angle of view.

• A group of Chromis adds not just color but also constant motion to reef aquariums, simulating the activity of a natural reef.