Black-bar Chromis (Chromis retrofasciata)

The Black-bar Chromis is a small, distinctive member of the damselfish family, often overlooked in favor of its brighter relatives. However, it is a favorite among nano-reef enthusiasts and those who appreciate subtle, graphic patterns. Its most defining feature is a single, bold vertical black bar that separates the pale-tan or yellowish front of the body from a stark, snow-white tail.

Key Information

• Common Names: Black-bar Chromis, Black-bar Puller

• Scientific Name: Chromis retrofasciata

• Origin: Western Pacific (Indonesia to Fiji, north to Japan)

• Max Size: 45 cm (approx. 2 inches) one of the smallest Chromis species.

• Lifespan: 58 years

• Temperament: Peaceful; relatively shy compared to other damselfish

• Diet: Omnivore/Planktivore Requires small, frequent feedings

• Care Level: Easy

Behaviour & Tank Compatibility

The Black-bar Chromis is unique because it is significantly less social than other members of its genus. While Green Chromis need a shoal to feel safe, the Black-bar is often found in the wild as a solitary individual or in very small, loose groups.

• Solitary Nature: It is perfectly happy being the only one of its species in a tank. If you do keep a group, ensure the tank is large enough to prevent squabbles over territory.

• Cryptic Behavior: Unlike the open-water cruising style of the Barrier Reef Chromis, this species prefers to stay close to the rockwork. It will often hover near a favorite coral or crevice, darting in for safety at the first sign of movement.

• Reef Safe: 100% Reef Safe. They are ideal for coral-heavy environments as they do not pick at any sessile invertebrates.

• Tank Mates: Excellent for nano reefs. Best kept with other peaceful, small fish like Trimma Gobies, Blennies, and Firefish. Avoid large, aggressive tank mates that might intimidate this shy species.

Ideal Tank Setup

• Tank Size: Due to its tiny size and lower activity level, a single specimen can be kept in a tank as small as 40L75L (1020 Gallons).

• Rockwork: Requires intricate rockwork with many small holes. They are naturally found among Acropora or other branching corals where they can quickly hide between branches.

• Flow: Prefers moderate water movement. They are not strong swimmers compared to their larger cousins and shouldn’t be blasted by high-power wavemakers.

• Feeding: They have small mouths and high metabolisms. Feed 23 times daily with finely shaved frozen mysis, cyclops, or high-quality micro-pellets.

Why Choose the Black-bar Chromis?

The Black-bar Chromis is the perfect “boutique” fish for a specialized nano reef. Its high-contrast black and white rear provides a sophisticated look that stands out against colorful corals without being visually overwhelming. Because it doesn’t require a large school to thrive, it is one of the most practical choices for hobbyists with limited space who still want the classic “Chromis look” and hardy nature.