How big does Cardinal Tetra get?

Cardinal Tetra reaches an adult standard length of 2.5–3 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 Cardinal Tetra need?

23–28 °C, pH 5–6.8, 1–6 dGH, 0–4 dKH. At 5 °C wide it is one of the more forgiving ranges.

What is the smallest tank for Cardinal 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 Cardinal Tetra like to keep?

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

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

The checker returns "Keep with care". The shared temperature window is only 27–28 °C (1 °C wide). A heater fault or a summer heatwave will push the tank past one side's limit — run a separate thermostat as a backup.

G-01 / 07Freshwater

Cardinal Tetra宝莲灯

Paracheirodon axelrodi · Characidae

The neon tetra with a full-length red stripe, and a stricter demand for warm soft water.

Illustration to come

G-01 / 07 · Cardinal Tetra Paracheirodon axelrodi

SpecificationsFish atlas

Name: 宝莲灯
Scientific name: Paracheirodon axelrodi
Family: Characidae
Origin: Upper Negro and Orinoco river basins, South America
Adult size: 2.5–3 cm
Temperament: Peaceful
Diet: Carnivore
Water level: Middle
Level: Moderate
School size: ≥ 6
Min. tank: 40 L
Min. length: 50 cm
Plant safe: Leaves plants alone

Water requirementsFreshwater

Temp.23–28 °C

pH5–6.8

Hardness1–6 dGH

Alkalinity0–4 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

1Needs warm, soft water even more than the neon tetra; below 24 °C it slowly thins and fades.
2Mostly wild-caught, so quarantine before stocking and watch for internal parasites and bacterial infection.
3Keep eight or more over dark substrate and dense plants for the deepest red.
4A classic discus tankmate, though both demand zero ammonia and nitrite.

Check a tank mate

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

Frequently asked questions

How big does Cardinal Tetra get?: Cardinal Tetra reaches an adult standard length of 2.5–3 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 Cardinal Tetra need?: 23–28 °C, pH 5–6.8, 1–6 dGH, 0–4 dKH. At 5 °C wide it is one of the more forgiving ranges.
What is the smallest tank for Cardinal 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 Cardinal Tetra like to keep?: Temperament: peaceful. Difficulty: moderate. It occupies the middle and is carnivore. With plants it is "Leaves plants alone".
Can Cardinal Tetra be kept with its most common tank mate?: The checker returns "Keep with care". The shared temperature window is only 27–28 °C (1 °C wide). A heater fault or a summer heatwave will push the tank past one side's limit — run a separate thermostat as a backup.