Neon tetra

Paracheirodon innesi

FreshwaterFish

Care at a glance

Temperature: 70–77°F (21–25°C)
pH: 5.0–7.5
Adult size: 1.5 in (3.8 cm)
Minimum tank: 11 gal (40 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Beginner
Breeding: Hard
Rarity: Very common
Origin: Peru, Colombia, Brazil
Family: Characidae

Overview

Keep them in a group of at least six, ideally more, in a tank of 40 liters or up. They're peaceful and sit in the middle of the water column, schooling tightly when something spooks them. Water should run cool to room temperature, roughly low to mid 20s C, soft, and acidic to neutral. Feed small flakes, micro pellets, and the odd frozen treat like daphnia or baby brine, and keep tankmates small and gentle.

In the wild

Neon tetras come from soft, slightly acidic blackwater streams in the western Amazon, across Peru, Colombia, and Brazil. These are dim, tannin-stained creeks shaded by forest canopy. To match that, give them a planted tank with some floating cover, dark substrate, and soft water on the acidic side. They show their best color in lower light.

Good to know

This is a small characin in the family Characidae, topping out around 3 to 4 cm. It's an egg scatterer with no parental care, and a healthy adult can live several years. Wild stocks have declined in places from deforestation and pollution, though the species itself isn't threatened. Most fish in the trade today are commercially bred.

Did you know

That blue line isn't pigment. It's a layer of reflective cells called iridophores, and the fish can shift the angle of those crystals to change how the stripe looks. At night the blue fades almost to gray, then comes back when the lights are on.