Turquoise Rainbowfish (Melanotaenia lacustris)

The Turquoise Rainbowfish (Melanotaenia lacustris) is a popular aquarium fish. This profile covers habitat, appearance, tank setup, water parameters, diet, compatibility, breeding, and health — focused on turquoise rainbowfish care at home.

For related reading, see Forktail Blue-eye, Java Moss and White Cloud Mountain Minnow.

Natural Habitat and Origin

Turquoise Rainbowfishs come from Lake Kutubu, Papua New Guinea. Recreate calm, planted areas with stable water for best color and behavior.

Appearance and Size

Adults reach about 4–5 inches (10–12 cm). Look for clear eyes, intact fins, and active swimming when selecting stock.

Tank Size and Setup

Plan for 40 gallon (150 L)+. Use plants, driftwood, and open swimming lanes. Gentle filtration suits most community species.

Water Conditions

• Temperature: 72–79°F (22–26°C)
• pH: 7.0–8.0
• Ammonia / nitrite: always 0 ppm

Diet and Feeding

Natural diet: omnivore. Offer quality flakes or micro pellets plus frozen or live foods several times weekly.

Compatibility

Keep in groups of 6+ when schooling applies. Avoid aggressive or predatory tank mates that outcompete or harass them.

Breeding

Condition with live foods, provide spawning sites or plants, and protect eggs or fry from adults. Species-specific details vary — observe pairs in a dedicated breeding setup when possible.

Health and Care Level

Overall care: beginner. Quarantine new fish, maintain weekly water changes, and address water quality before medicating.

Conclusion

With appropriate tank size, stable parameters, and compatible neighbors, Melanotaenia lacustris makes a rewarding display species for attentive keepers.