Pygmy Rainbowfish

Pygmy Rainbowfish (Melanotaenia pygmaea)

Also known as the Kimberley Pygmy Rainbowfish

A tiny and rare freshwater rainbowfish endemic to just two small tributaries of the Prince Regent River in the remote West Kimberley region of northwestern Australia. One of the smallest rainbowfish species, it is prized in the aquarium hobby for its compact size, metallic iridescence, and lively schooling behavior in a miniature package.

Key Features

• Maximum Size: 5.5 cm / ~2.2 inches SL (commonly around 4.0 cm / ~1.6 inches; males larger than females).
• Appearance: Compact, fusiform body built for active swimming. Mature males display striking metallic sky-blue to turquoise coloration with reddish-orange accents on the head, snout, breast, and belly; fins are pale to whitish. Females are smaller and more subdued with silvery-blue tones and a faint dark midlateral stripe. Colors intensify beautifully under good lighting and with a varied diet.
• Fin Details: Dorsal spines 5–7, dorsal soft rays 8–11; anal spines 1, anal soft rays 14–18.

Aquarium Care

• Tank Size: Minimum 30–40 gallons for a small school (6 or more recommended for best coloration and natural behavior).
• Water Parameters: Tropical freshwater; 72–82°F (22–28°C), pH 6.5–8.0, moderate hardness. Appreciates moderate water movement to mimic its natural stream habitat.
• Diet: Omnivorous — readily accepts high-quality flakes, micro-pellets, frozen, and live foods. A varied diet helps maintain vibrant colors.
• Behavior: Peaceful, active mid-to-upper water column schooling fish (often seen in groups of 50+ in the wild). Excellent for planted nano to medium community aquariums with similarly sized, non-aggressive companions. Provide a tight-fitting lid as they are good jumpers

IUCN Status: Vulnerable (VU)

Add shimmering metallic blue brilliance and lively miniature schooling action to your aquarium with the beautiful Pygmy Rainbowfish!