All fish / Characidae

January Tetra

Hemigrammus hyanuary

Also known as january tetra, green neon tetra (misapplied), costello tetra, hyanuary tetra, green tetra, ハイアニュアリー, 一月灯, 一月灯鱼

A small, slim tetra with a translucent silvery body, a shimmering green to turquoise line along the upper flank and a dark spot at the base of the tail with a gold highlight above it. It is kept for its hardiness and calm nature, and a large shoal looks lively in planted community tanks.

Care at a glance

Care level

Easy

Temperament

Peaceful

Adult size

3.5 cm

Temperature

23 to 28 °C

pH

6 to 7.5

Smallest tank

60 litres

Keep as

Shoal of 8 or more

Diet

Omnivore: quality flakes and micro pellets with live or frozen daphnia, brine shrimp and bloodworm

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Upper Amazon basin in Brazil, Colombia and Peru, including Lake Hyanuary near Manaus

Breeding

It scatters eggs over fine-leaved plants or spawning mops and gives no parental care, so adults should be removed after spawning. Soft, slightly acidic water and dim light help, and breeding is achievable for hobbyists with some experience.

Good to know

Often confused with the green neon tetra (Paracheirodon simulans), which has a full blue-green stripe and needs softer water. Keep it away from large fish that could eat it.