Lake Kutubu Rainbow Fish (Melanotaenia lacustris)

Lake Kutubu Rainbow Fish (Melanotaenia lacustris)

The Lake Kutubu Rainbow Fish, also known as the Turquoise Rainbow Fish, is a stunning freshwater species native to Papua New Guinea. Renowned for its shimmering turquoise-to-blue coloration and active swimming behavior, this peaceful schooling fish is a popular choice for community aquariums. Its hardiness and adaptability make it suitable for aquarists of all experience levels.

Natural Habitat

Lake Kutubu Rainbow Fish are endemic to Lake Kutubu and its surrounding tributaries in Papua New Guinea. These waters are crystal clear, moderately hard, and slightly alkaline, with dense aquatic vegetation and rocky substrates.

Aquarium Care

Tank Requirements

• Minimum Tank Size: 120 liters for a group of 6 or more individuals.
• Water Temperature: 22–28°C.
• pH Range: 7.0–8.0.
• Water Hardness: 10–20 dGH (moderately hard water).
• Filtration: Strong filtration and moderate water flow to replicate their natural environment.

Aquascaping

• Substrate: Sand or fine gravel.
• Decor: Include rocks, driftwood, and caves for a natural aesthetic.
• Plants: Use live plants such as Vallisneria, Java Fern, Cryptocoryne, or Anubias. Floating plants can provide shade and diffuse light.
• Lighting: Bright lighting enhances their iridescent coloration.

Tank Mates

Lake Kutubu Rainbow Fish are peaceful and do well in community tanks with other non-aggressive species. Suitable tank mates include:

• Schooling fish like tetras, rasboras, and danios.
• Bottom-dwellers such as Corydoras or small plecos.
• Other rainbow fish species or livebearers.
  Avoid: Large, aggressive, or fin-nipping species.

Feeding

Lake Kutubu Rainbow Fish are omnivorous and thrive on a varied diet:

• Staple Foods: High-quality flakes or pellets formulated for tropical fish.
• Protein: Live or frozen foods such as brine shrimp, daphnia, and bloodworms.
• Vegetable Matter: Offer blanched spinach, zucchini, or spirulina-based foods regularly.
  Feed 1–2 times daily in small portions to prevent overfeeding and maintain water quality.

Behavior and Personality

• Activity: Active swimmers that occupy the middle and upper levels of the aquarium.
• Social Behavior: They are schooling fish and should be kept in groups of at least 6 to reduce stress and promote natural behaviors.
• Peaceful Nature: They are compatible with a variety of community tank setups and rarely display aggression.

Breeding

Breeding Lake Kutubu Rainbow Fish is straightforward with the right conditions.

Sexing

• Males: More vibrant and display a deeper blue coloration, with elongated dorsal and anal fins.
• Females: Slightly smaller with a duller, silvery appearance.

Breeding Tank Setup

• Use a separate breeding tank of at least 50 liters with soft, slightly alkaline water.
• Provide spawning mops or fine-leafed plants for egg-laying.
• Maintain water temperature at 26–28°C.

Breeding Process

1. Condition adults with live or frozen foods to encourage spawning.
2. Males display to females by spreading their fins and intensifying their colors.
3. Eggs are scattered on plants or mops and hatch within 7–10 days.

Fry Care

• Feed fry with infusoria or liquid fry food initially.
• Transition to baby brine shrimp or finely powdered flakes as they grow.

Key Notes

• Behavior: These fish thrive in well-maintained tanks with plenty of swimming space and stable water conditions.
• Coloration: Their vibrant turquoise color intensifies with age and optimal water quality.
• Maintenance: Regular water changes and a balanced diet are essential to maintain their health and vivid appearance.

The Lake Kutubu Rainbow Fish (Melanotaenia lacustris) is a dazzling species that brings energy, color, and grace to medium or large aquariums. Its peaceful nature, adaptability, and stunning iridescence make it a rewarding choice for community setups and dedicated rainbow fish tanks.