Zebra danio

Danio rerio

FreshwaterFish

Care at a glance

Temperature: 64–75°F (18–24°C)
pH: 6.0–7.5
Adult size: 2 in (5 cm)
Minimum tank: 15 gal (55 L)
Temperament: Mostly peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Beginner
Breeding: Medium
Rarity: Very common
Origin: Eastern India, Bangladesh
Family: Cyprinidae

Overview

Keep them in a group of at least five or six. They are constant, fast swimmers that cruise the middle and top of the tank. They are hardy, peaceful, and a good beginner fish, though their energy can pester slow or long-finned tankmates. They eat just about anything, including flake, small pellets, and live or frozen foods like brine shrimp and bloodworms.

In the wild

Zebra danios come from streams, rivers, and rice paddies across eastern India and Bangladesh, in shallow, slow to moderate water with some plants. They handle cooler temperatures than most tropicals, doing fine in the high teens to low 20s C, which makes them one of the few community fish that work in an unheated room. Give them open swimming space and a current, since they are built for moving water.

Good to know

This is a small cyprinid, in the same family as carp and barbs, growing to about 5 cm. They are egg scatterers and breed readily, dropping eggs over the bottom with no parental care afterward. The IUCN lists them as Least Concern. They are also a major laboratory animal, which has made their biology unusually well documented.

Did you know

It was one of the first vertebrates to have its genome fully sequenced, and see-through versions called Casper, plus glowing GloFish, were both developed from this species in research labs.