Red Rainbow Fish (Glossolepis incisus)

The Red Rainbow Fish (Glossolepis incisus), commonly known as the Salmon Red Rainbowfish or New Guinea Red Rainbowfish, is one of the most brilliantly colored rainbowfish species available. Native to Lake Sentani in Irian Jaya (West Papua), Indonesia, males in breeding condition develop an intense blood-red to salmon coloration over their deep, laterally compressed bodies. Females are more modestly colored in olive-brown to yellow-green.

This species grows to about 12–15 cm and is best housed in a large aquarium of at least 200 liters with ample swimming space. Like most rainbowfish, G. incisus is active and rewards the keeper with spectacular displays, especially in the morning when fish are most active and colorful. Males compete with each other through parallel swimming and fin displays rather than physical aggression.

Red Rainbowfish are hardy and adaptable to a range of water conditions, though they appreciate neutral to slightly alkaline, moderately hard water that mirrors their highland lake origin. A varied diet high in plant matter and protein is important for maintaining their vivid coloration.

They are peaceful with other fish and make excellent community aquarium residents alongside other rainbowfish, larger tetras, and peaceful cichlids. Their active nature means they need open swimming space and should not be kept in cramped conditions.

Water Parameters: Red Rainbowfish prefer neutral to slightly alkaline water: pH 7.0–8.0, temperature 22–28°C, GH 8–20, KH 4–12. They are from a highland lake and appreciate moderately hard, clean water. Good filtration with moderate flow is important.

Tank Setup: Minimum 200 liters for a group. Provide open swimming space in the middle of the tank with robust planted areas along the sides and back. Vallisneria and Sagittaria work well. Use a fine-gravel or sandy substrate. These are active jumpers — a secure lid is essential.

Feeding: Omnivores with a preference for plant matter. Offer high-quality flake food, spirulina flakes, medium pellets, frozen bloodworm, brine shrimp, and daphnia. Spirulina and vegetable-based foods enhance red coloration. Feed twice daily.

Tankmates: Compatible with other rainbowfish, larger peaceful tetras, barbs, gouramis, and peaceful cichlids. Avoid housing with fin-nippers. Males display impressive courtship behavior toward each other and females — keep a ratio of 1 male to 2 females to reduce male stress.

Health: Robust and disease-resistant when kept in good conditions. Sensitive to poor water quality — maintain weekly 30% water changes. Watch for ich and internal parasites. Avoid overfeeding, which leads to water quality issues.