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FishbeginnerSaltwater

Three-stripe Damsel

Dascyllus aruanus

AnimaliaChordataActinopterygiiPerciformesPomacentridae

📍 Indo-Pacific

Ask Finn

Classic white body with three bold vertical black bars. One of the first marine fish to breed in captivity. Extremely hardy and cheap — often used to cycle tanks. Territorial and aggressive toward other damsels.

Size4"
Min Tank30g
School5+
aggressive
Zonemid

Care Guide

Diet

Three-stripe Damsels are omnivores that thrive on a varied diet of high-quality marine flakes, pellets, and frozen foods like brine shrimp and mysis shrimp. Feed small portions once daily, offering only what they can consume in 2-3 minutes. Supplement occasionally with algae-based foods or nori to support digestive health.

Behavior

Extremely hardy and active swimmers that occupy the mid-water column, darting rapidly throughout the tank. They are highly territorial and aggressive toward other damsels and similarly-sized fish, especially as they mature; schooling works best when kept in groups of 5+ from a young age to establish hierarchy. They are bold, confident fish that readily accept food and adapt well to captive conditions.

Breeding

Three-stripe Damsels were among the first marine fish bred successfully in captivity and remain relatively easy to breed in home aquariums. Breeding pairs are highly aggressive and territorial; provide plenty of hiding spots and a separate breeding tank if possible. Eggs are laid on hard surfaces and guarded fiercely by parents; fry are planktonic and require microscopic foods like rotifers initially.

Common Diseases

Ich (Marine White Spot Disease)

Symptoms

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

Treatment

Raise temperature to 28-29°C, maintain excellent water quality, use copper-based treatments or hyposalinity therapy; quarantine affected fish if possible

Fin Rot

Symptoms

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

Treatment

Improve water quality and reduce aggression stress; perform frequent water changes; use antibiotic treatments if secondary bacterial infection occurs

Velvet (Oodinium)

Symptoms

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

Treatment

Raise temperature to 28-29°C, reduce light exposure, use copper treatments or formalin-based medications; maintain pristine water conditions

Bacterial Infection

Symptoms

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

Treatment

Perform large water changes, improve tank conditions, use broad-spectrum antibiotics if available; isolate severely affected fish

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Quick Facts

pH
8.1–8.4
diet
omnivore
maxSize
4 inches
salinity
SG 1.020–1.025
minTankSize
30 gallons
temperature
75–82°F (24–28°C)

Temperature

75–82°F

24–28°C

Stats

Community tips0
Kept by0 hobbyists