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FishintermediateFreshwater

Millennium Rainbowfish

Glossolepis pseudoincisus

AnimaliaChordataActinopterygiiAtheriniformesMelanotaeniidae

📍 Lake Ifaten, Papua New Guinea

Ask Finn

Males develop intense red-orange coloration. A hardy and peaceful rainbowfish that does well in planted community tanks.

Size4"
Min Tank30g
School6+
peaceful
Zonemid

Care Guide

Diet

Millennium Rainbowfish are omnivores that thrive on a varied diet of high-quality flake foods, micro pellets, and small frozen foods like brine shrimp and daphnia. Feed small amounts once daily, offering only what they can consume in 2-3 minutes. Supplement occasionally with vegetable matter such as blanched spinach or spirulina-based foods to support their vibrant coloration.

Behavior

These peaceful, active fish are schooling species that spend most of their time in the mid-water column, occasionally rising to the surface. Males display territorial behavior toward each other but rarely cause serious harm; they exhibit their most intense red-orange coloration during social interactions and feeding times. They are curious and responsive to tank activity, making them engaging community fish.

Breeding

Breeding Millennium Rainbowfish in captivity is moderately difficult and rarely achieved by hobbyists. They require pristine water conditions, dense vegetation for egg scattering, and a separate breeding tank to protect fry from predation. Success requires patience, as spawning is not guaranteed even with optimal conditions.

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

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

Treatment

Raise temperature gradually to 28-29°C, perform daily 25% water changes, use aquarium salt or ich medication; treat for 7-10 days

Fin Rot

Symptoms

Frayed or deteriorating fins, discoloration at fin edges, lethargy

Treatment

Improve water quality with frequent partial water changes, reduce stocking density, use antibacterial medication if severe

Columnaris (Flexibacter columnaris)

Symptoms

Whitish film on body, mouth rot, fin damage, loss of appetite

Treatment

Increase water changes, maintain optimal temperature (24-26°C), use antibacterial medication; isolate affected fish if possible

Parasitic Infections

Symptoms

Excessive scratching, visible parasites, clamped fins, weight loss

Treatment

Use anti-parasitic medication, maintain excellent water quality, quarantine new fish before adding to main tank

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Quick Facts

pH
6.5–7.5
diet
omnivore
maxSize
4 inches
minTankSize
30 gallons
temperature
72–79°F (22–26°C)

Temperature

72–79°F

22–26°C

Stats

Community tips0
Kept by0 hobbyists