Lake Kutubu Rainbowfish – Stunning Turquoise-Blue Freshwater Rainbowfish
The Lake Kutubu Rainbowfish (Melanotaenia lacustris) is a spectacular freshwater fish prized for its brilliant turquoise-blue coloration, shimmering metallic scales, and elegant swimming behaviour.
Native to the crystal-clear waters of Lake Kutubu in Papua New Guinea, this remarkable rainbowfish displays beautiful shades of sky blue, turquoise, and blue-green that change subtly with lighting, mood, and maturity.
Mature males develop particularly intense coloration, deeper bodies, and impressive displays during courtship. Females typically feature softer blue-silver tones, adding natural contrast to the group.
Peaceful, active, and highly social, Lake Kutubu Rainbowfish thrive in spacious planted aquariums with open swimming areas and stable water conditions.
Their striking colour, graceful movement, and engaging schooling behaviour make them an outstanding centerpiece for larger freshwater community aquariums.
Care Guide
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Parameter
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Details
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Scientific Name
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Melanotaenia lacustris
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Common Name
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Lake Kutubu Rainbowfish
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Other Names
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Turquoise Rainbowfish, Blue Rainbowfish
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Origin
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Lake Kutubu and Soro River, Papua New Guinea
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Adult Size
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Approximately 10–12 cm
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Temperature
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22–27°C
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pH
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7.0–8.0
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Water Hardness
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9–15 dGH
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Minimum Tank Size
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200 L+ recommended
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Minimum Tank Length
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120 cm
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Diet
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Omnivore
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Temperament
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Peaceful, active
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Care Level
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Easy to Intermediate
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Group Size
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6 minimum; preferably 8–10+
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Lifespan
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Approximately 5–8 years
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Swimming Level
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Middle / Upper
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Water Flow
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Gentle to Moderate
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Aquarium Type
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Planted Aquarium / Community Aquarium
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Special Requirements
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Open swimming space, group housing, stable water, secure lid
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