Pagwi Rainbowfish

North New Guinea Rainbowfish (Melanotaenia affinis) 

AKA: Pagwi Rainbowfish

A vibrant and hardy freshwater rainbowfish widespread across New Guinea. One of the more common and popular rainbowfish species in the aquarium hobby, it is prized for its active schooling behavior and the brilliant colors that develop in mature males.

Key Features

• Maximum Size: 11.5 cm / ~4.5 inches SL (males larger; females reach ~4 inches).
• Appearance: Sleek, fusiform body. Males display striking iridescent blue tones with a prominent blue midlateral line and red accents in the fins and body; females are generally more subdued with silvery to pale golden hues.
• Fin Details: Dorsal spines 5–7, dorsal soft rays 13–20; anal spines 1, anal soft rays 18–24.

Aquarium Care

• Tank Size: Minimum 55 gallons for a small school (6 or more recommended for best color and natural behavior).
• Water Parameters: Tropical freshwater; 68–86°F (20–30°C), pH 6.5–8.0, moderate hardness.
• Diet: Omnivorous — readily accepts high-quality flakes, pellets, frozen, and live foods.
• Behavior: Peaceful, active mid-to-upper water column schooling fish. Excellent for planted or community aquariums with similarly sized, non-aggressive companions. Provide a tight-fitting lid as rainbowfishes are known to jump.

IUCN Status Least Concern (LC)

Add brilliant iridescent blues and lively schooling action to your aquarium with the beautiful North New Guinea Rainbowfish!