Phoenix rasbora

Boraras merah

FreshwaterFish

Care at a glance

Temperature: 72–81°F (22–27°C)
pH: 5.0–7.0
Adult size: 0.8 in (2 cm)
Minimum tank: 11 gal (40 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: Medium
Rarity: Common
Origin: Southern Borneo (Kalimantan Tengah, Indonesia)
Family: Cyprinidae

Overview

Keep them in a school of 8 to 10, ideally 12 or more, in a tank of 40 liters or up, since a bigger group brings out the deep red and steadier behavior. They are peaceful and tend to hold in the middle of the water column, moving together when something passes. Keep the water at 22 to 27 C, soft, and acidic to neutral at a pH of 5 to 7, with gentle sponge filtration on a stable, mature tank. The mouth is tiny, so feed small foods like microworms, baby brine, and crushed flake. They are safe with shrimp, snails, and fry, and do best with other small, gentle tankmates.

In the wild

Phoenix rasboras come from soft, acidic blackwater in southern Borneo, in the peat swamps and slow forest streams of Kalimantan Tengah, Indonesia. The water there is stained brown with tannins from leaf litter and fallen botanicals, and the light is dim under plant cover. To match that, give them fine sand, driftwood, dense planting with some floating cover, and a handful of leaf litter to release tannins. Keep them in 40 liters or more, at 22 to 27 C, with a pH on the acidic side, roughly 5 to 7.

Good to know

This is Boraras merah, a tiny cyprinid in the family Cyprinidae, and one of the smallest aquarium fish at about 1.5 to 2 cm full grown. It is an egg scatterer with no parental care, and getting fry to survive takes a mature tank and small live foods, so breeding sits at a medium difficulty. A healthy adult can live a few years. Most fish in the trade are wild caught, though tank-bred stock turns up too.

Did you know

The name merah is Indonesian for red, and the color is the whole point of keeping them. In bright bare tanks they often wash out to a pale orange, but over dark substrate with tannin-stained water and plenty of their own kind, the males deepen to a solid brick red. The color tells you the tank conditions are right.