Azure tetra

Care at a glance

Overview

The azure tetra is a tiny, glassy, near-transparent characin that shows a soft blue sheen in the right light. Keep it in a group of six or more; it schools, and a tight group in tannin-stained water is the whole display. It swims in the middle of the tank and is peaceful toward fish it cannot eat, but as a small predator it should not share a tank with newly hatched fry or the smallest shrimp. Give it calm, similarly small companions. Feed small foods such as microworm, baby brine shrimp, crushed flake, and fine frozen items. A school is at home in a tank of around 54 liters or more.

In the wild

The azure tetra lives in dim, soft, acidic blackwater in the Orinoco and Negro basins, where its faint shine stands out in tea-colored water. Recreate that with soft, tannin-stained water, driftwood, leaf litter, and low light. Keep it warm, around 23 to 28 C, and distinctly acidic at pH 4.5 to 6.8. Dark water and gentle lighting bring out the blue far better than a bright tank.

Good to know

Heterocharax virgulatus is a small predatory characin in the family Acestrorhynchidae, described in 2000, and reaches only about 4 centimeters. Its body is glassy and semi-transparent, carrying a pale blue sheen; the species name virgulatus refers to a fine streak or stripe. It is a micro-predator despite its size. Its spawning has not been documented in captivity.

Did you know

Described only in 2000, it is nearly see-through, yet a cool blue shine plays over its glassy body, which is why the trade calls it the azure or sapphire tetra even though it carries almost no true pigment.

Common questions

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