Domino Damsel

Dascyllus trimaculatus

Animalia›Chordata›Actinopterygii›Perciformes›Pomacentridae

📍 Indo-Pacific

Bold black damsel with three white spots — like a domino. Juveniles shelter in anemones and sea urchins. One of the hardiest marine fish ever kept. Grows aggressive as an adult. Often used to cycle new tanks.

Size5.5"

Min Tank30g

aggressive

Zonemid

Care Guide

Diet

Domino Damsels are omnivores and should be fed a varied diet once daily in small portions. Offer high-quality marine flakes, small pellets, frozen mysis shrimp, and brine shrimp. Supplement with algae-based foods or blanched vegetables occasionally to support overall health and coloration.

Behavior

Domino Damsels are bold and active swimmers that occupy mid-water zones. Juveniles are relatively peaceful and often shelter in anemones or corals, but adults become increasingly territorial and aggressive toward other fish, especially similar-sized species. They are hardy and adaptable, making them popular for cycling new tanks despite their aggressive tendencies.

Breeding

Breeding Domino Damsels in captivity is difficult and rarely achieved in home aquariums. They are substrate spawners that require specific environmental triggers and significant space. Success requires pristine water conditions, minimal disturbance, and removal of eggs to a separate rearing tank with specialized care.

Tank Mates

Ocellaris Clownfish

Similar size and hardiness; both can be aggressive but may coexist in larger tanks with adequate space and hiding spots

good

Pink Skunk Clownfish

Comparable temperament and water requirements; clownfish can hold their own against damsel aggression

good

Neon Goby

Small size makes them vulnerable; only suitable in larger tanks where they can maintain distance

caution

Cleaner Shrimp

May be nipped at or harassed; provide dense cover and multiple hiding spots for shrimp safety

caution

Nerite Snail

Hard shell provides protection; snails are generally ignored by damsels and help with algae control

good

Common Diseases

Ich (Marine Ich)

Symptoms

White spots on body and fins, rapid breathing, rubbing against surfaces, lethargy

Treatment

Raise temperature gradually to 28-29°C, perform daily 25% water changes, use copper-based or formalin treatments; quarantine infected fish if possible

Fin Rot

Symptoms

Frayed or deteriorating fins, discoloration at fin edges, progressive fin loss

Treatment

Improve water quality with frequent partial changes, maintain stable parameters, use antibiotic treatments or medicated foods; ensure adequate water flow

Velvet Disease

Symptoms

Fine golden or rust-colored dust on body, rapid breathing, loss of appetite, scratching behavior

Treatment

Increase aeration and temperature to 28-29°C, perform daily water changes, use copper treatments or formalin; quarantine affected fish immediately

Bacterial Infections

Symptoms

Open sores, cloudy eyes, swollen abdomen, torn fins, behavioral changes

Treatment

Improve water quality, perform frequent partial water changes, use broad-spectrum antibiotics or medicated foods; isolate severely affected individuals