Boeseman's Rainbowfish

Boeseman's Rainbowfish (Melanotaenia boesemani)

A stunning and iconic freshwater rainbowfish endemic to the Ajamaru Lakes region and nearby Aitinjo Lake in the Vogelkop Peninsula of Irian Jaya (West Papua), Indonesia. Highly prized in the aquarium hobby for its dramatic bicolor pattern in males and peaceful schooling nature.

Key Features

• Maximum Size: 9.0 cm / ~3.5 inches SL (males larger; females up to ~2.8 inches).
• Appearance: Sleek, fusiform body. Males are famous for their striking bicolor pattern — brilliant electric blue on the front half transitioning to vibrant orange-red on the rear half. Females are slimmer with more subdued silvery-gold to pale blue tones.
• Fin Details: Dorsal spines 5–7, dorsal soft rays 10–14; anal spines 1, anal soft rays 17–23.

Aquarium Care

• Tank Size: Minimum 55 gallons for a small school (6 or more recommended for best coloration and natural behavior).
• Water Parameters: Tropical freshwater; 81–86°F (27–30°C), pH 7.0–8.0, moderate to hard water (dH 9–19).
• Diet: Omnivorous — readily accepts high-quality flakes, pellets, frozen, and live foods. A varied diet enhances coloration.
• Behavior: Peaceful, active mid-to-upper water column schooling fish. Excellent for planted community tanks with similarly sized, non-aggressive companions. Provide a tight-fitting lid as they are known to jump.

IUCN Status Endangered (EN)

Add brilliant blue-and-orange bicolor males and lively schooling action to your aquarium with the beautiful Boeseman's Rainbowfish!

Average Large purchase size: ~3-4.5"

Average Small purchase size: ~1-2"

Average adult size: ~4.5