How big does Neon Tetra get?

Neon Tetra reaches an adult standard length of 2.5–3.5 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.

What water does Neon Tetra need?

20–26 °C, pH 5.5–7, 1–10 dGH, 0–5 dKH. At 6 °C wide it is one of the more forgiving ranges.

What is the smallest tank for Neon Tetra?

At least 40 L, and no shorter than 50 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 6 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.

What is Neon Tetra like to keep?

Temperament: peaceful. Difficulty: beginner. It occupies the middle and is carnivore. With plants it is "Leaves plants alone".

Can Neon Tetra be kept with its most common tank mate?

The checker returns "Can be kept together". Neon Tetra and Cardinal Tetra is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".

G-01 / 06Freshwater

Neon Tetra红绿灯

Paracheirodon innesi · Characidae

A neon blue line over half a red stripe: the best known first tropical fish.

Illustration to come

G-01 / 06 · Neon Tetra Paracheirodon innesi

SpecificationsFish atlas

Name: 红绿灯
Scientific name: Paracheirodon innesi
Family: Characidae
Origin: Amazon basin, South America (Brazil, Peru, Colombia)
Adult size: 2.5–3.5 cm
Temperament: Peaceful
Diet: Carnivore
Water level: Middle
Level: Beginner
School size: ≥ 6
Min. tank: 40 L
Min. length: 50 cm
Plant safe: Leaves plants alone

Water requirementsFreshwater

Temp.20–26 °C

pH5.5–7

Hardness1–10 dGH

Alkalinity0–5 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Keeping notes

1Start with six, ideally ten or more; singletons or pairs hide and fade from stress.
2Prefers soft, acidic water and catches ich easily in immature tanks, so wait a month before adding them.
3A micropredator: feed micro granules and baby brine shrimp, since oversized pellets are simply spat out.
4Best with cardinals and rummy-nose tetras, but avoid angelfish that outgrow and swallow them.

Check a tank mate

Jump straight to the verdict for Neon Tetra against this one — no need to pick it again.

Frequently asked questions

How big does Neon Tetra get?: Neon Tetra reaches an adult standard length of 2.5–3.5 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.
What water does Neon Tetra need?: 20–26 °C, pH 5.5–7, 1–10 dGH, 0–5 dKH. At 6 °C wide it is one of the more forgiving ranges.
What is the smallest tank for Neon Tetra?: At least 40 L, and no shorter than 50 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 6 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.
What is Neon Tetra like to keep?: Temperament: peaceful. Difficulty: beginner. It occupies the middle and is carnivore. With plants it is "Leaves plants alone".
Can Neon Tetra be kept with its most common tank mate?: The checker returns "Can be kept together". Neon Tetra and Cardinal Tetra is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".