Fly River Rainbowfish

Fly River Rainbowfish (Melanotaenia sexlineata)

Also known as the Six-lined Rainbowfish or Lipstick Rainbowfish

A rare and attractive freshwater rainbowfish endemic to small rainforest creeks in the upper Fly River system near Kiunga, Papua New Guinea. Noted for its distinctive striped pattern and the charming red lips often displayed by males, this species brings subtle elegance and lively schooling to the aquarium.

Key Features

• Maximum Size: 7.3 cm / ~2.9 inches SL (reaching up to ~3.5 inches total length).
• Appearance: Fusiform body that becomes deeper in mature males. Lemon-greenish to silvery base color accented by 5–8 narrow dark stripes, with a prominent darker midlateral band. Males frequently show bright red lips (“lipstick” appearance) and have more elongated, pointed dorsal and anal fins. Females are slimmer with softer, less defined markings.
• Fin Details: Dorsal spines 6–8, dorsal soft rays 10–12; anal spines 1, anal soft rays 16–19.

Aquarium Care

• Tank Size: Minimum 40 gallons for a small school (6 or more recommended for best coloration and schooling behavior).
• Water Parameters: Tropical freshwater; 75–82°F (24–28°C), pH 6.5–7.5, moderate hardness.
• Diet: Omnivorous — accepts high-quality flakes, pellets, frozen, and live foods.
• Behavior: Peaceful, active mid-to-upper water column schooling fish. Excellent for planted community tanks with similarly sized peaceful companions. Provide some vegetation and a tight-fitting lid as they may jump.

IUCN Status: Endangered (EN)

Add striking dark stripes and the unique “lipstick” look to your aquarium with the beautiful Fly River Rainbowfish!