Cardinal Tetra
Paracheirodon axelrodi
Also sold as Cardinals
Synonyms Cheirodon axelrodi · Red neon
Cardinal Tetra (Paracheirodon axelrodi) is a peaceful freshwater fish that reaches about 5 cm (2 in) and swims in open water in a shoal. It wants 75–84°F (24–29°C) and pH 4.5–7, is kept in groups of 8 or more, and needs a tank of at least 60 L (16 gal).
At a glance
| Type | Fish |
|---|---|
| Adult size | 5 cm (2 in) |
| Minimum tank | 60 L (16 gal) |
| Group size | 8 or more |
| Temperature | 75–84°F (24–29°C) |
| pH | 4.5–7 |
| Temperament | Peaceful |
| GH | 1–6 |
| Eats shrimp | Shrimplets only |
Before it goes in
- Cardinal Tetra needs at least 60 L (16 gal). The smallest size in this library that clears that is the Dennerle Nano Cube 60L.
- Keep 8 or more. Below that it hides, colours down and is far more likely to be picked on.
- Adult shrimp are safe; shrimplets will be eaten, so a shrimp colony will not grow in the same tank.
- It is the wrong size to share a tank with Goldfish, Angelfish and Axolotl: it ends up as food.
- It holds at 75–84°F (24–29°C). That shares a window with Betta and Cherry Shrimp, but not with Goldfish and Dojo Loach.
- A group of 8 takes up roughly 81% of what a Dennerle Nano Cube 60L will comfortably hold, so plan the rest of the stock around it.
What tank size does it need?
At least 60 L (16 gal). The smallest size here that clears it is the Dennerle Nano Cube 60L.
How many should I keep?
8 or more. Fewer than that and it spends its time hiding instead of out in the open.
Will it eat shrimp?
Adults are safe, shrimplets are not. You can keep shrimp with it; you just will not get a growing colony.
What water does it want?
75–84°F (24–29°C), pH 4.5–7, GH 1–6.
Good tank mates
- Tank mates from this library that share its temperature window, are peaceful and eat neither it nor its young: Cherry Shrimp, Bristlenose Pleco, Celestial Pearl Danio, Molly and Otocinclus.
- Plants that hold up with it: Hygrophila corymbosa 'Siamensis', Water Sprite, Anubias nana 'Petite' and Cryptocoryne wendtii.
Often compared with
| Cardinal Tetra | Neon Tetra | Green Neon Tetra | |
|---|---|---|---|
| Adult size | 5 cm | 3.5 cm | 2.5 cm |
| Min tank | 60 L | 40 L | 40 L |
| Group | 8+ | 6+ | 8+ |
| Temperature | 75–84°F (24–29°C) | 70–81°F (21–27°C) | 75–86°F (24–30°C) |
| Eats shrimp | Shrimplets only | Shrimplets only | Shrimplets only |
More livestock
Sources (4) · checked Sep 2026
- Mature tankaquariumsource.com
- What it eatsfishlaboratory.com
- Mature tanktankzen.co
- What it eatstropicflow.com