Neon rainbowfish

Melanotaenia praecox

FreshwaterFish

Care at a glance

Temperature: 73–82°F (23–28°C)
pH: 6.5–7.5
Adult size: 3.1 in (8 cm)
Minimum tank: 29 gal (110 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Hard
Rarity: Rare
Origin: New Guinea
Family: Melanotaeniidae

Overview

Neon rainbowfish are small, peaceful rainbows best kept in a group of six or more, where males light up in iridescent blue with red fins as they display to one another. They swim in the middle of the tank and make easy companions for other calm community fish of similar size. Their glow builds with a settled group and good food, so feed varied meals of fine flake or small pellet, frozen bloodworms, daphnia, and brine shrimp. Give them planted sides and open water to cruise. Aim for a tank around 110 liters or larger.

In the wild

This dwarf rainbowfish comes from the Mamberamo River basin in the north of western New Guinea, living in clear, flowing streams and tributaries among plants and wood. The water there is warm and runs neutral to slightly acidic, matching a pH of about 6.5 to 7.5 and a temperature between 23 and 28 degrees Celsius. Recreate it with fine substrate, driftwood, plenty of plants around the edges, and clean, gently moving water.

Good to know

Melanotaenia praecox is a member of Melanotaeniidae and stays small at about 8 centimeters, a true dwarf among rainbowfish. Males show the brightest blue body and red fins, while females carry yellowish fins and a plainer body. It is a continuous egg-scatterer that lays a few eggs a day onto fine plants and mops over weeks, without tending them. The tiny fry need small first foods and patient care, so breeding is rated hard.

Did you know

The name praecox means early, a nod to how young and small this fish matures and begins to spawn compared with its larger relatives. Its blue body and red fins are what many keepers picture when they think of a dwarf rainbowfish.