Red dwarf rasbora

Microrasbora rubescens

Also known as Redline rasbora, Rubescens rasbora

FreshwaterFish

Red dwarf rasbora (Microrasbora rubescens) — Rupert A. Collins · CC BY 3.0

Care at a glance

Temperature: 68–77°F (20–25°C)
pH: 7.0–8.0
Adult size: 1.2 in (3 cm)
Minimum tank: 12 gal (45 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Rare
Origin: Endemic to Inle Lake and its feeder waters in the Shan hills of Myanmar.
Family: Cyprinidae

Overview

Keep red dwarf rasboras in a group of at least eight to ten in a tank of 45 litres or more, with cool, slightly alkaline water at 20 to 25 C and a pH of 7.0 to 8.0. Keep the tank below 25 C, since they come from a cool lake and dislike sustained warmth. Feed small foods such as micropellets, crushed flake, and frozen daphnia and cyclops. They are peaceful schoolers that suit other cool-water nano fish.

In the wild

The red dwarf rasbora is found only in Inle Lake, a cool, high-altitude lake in the Shan hills of Myanmar. It forms large schools in the open midwater and around the edges among submerged plants. Because the lake sits high and stays cool and slightly alkaline, this fish likes conditions that are unusual for a small cyprinid. Wild fish show a warm red-orange flush along a slim silver body.

Good to know

Microrasbora rubescens is one of a handful of small fish restricted to Inle Lake, alongside the Lake Inle danio. Unlike most nano cyprinids it prefers cool, slightly alkaline water rather than warm blackwater. It reaches only about 3 cm and is easiest to keep and breed in a group.

Did you know

It is one of the few small aquarium fish that actually prefers hard, alkaline water, so it can suit tap water that would be wrong for most soft-water nano species.