Neon Tetra vs Cardinal Tetra
Two near-identical blue-and-red jewels for the community tank. The neon tetra is the hardier, cheaper classic; the cardinal tetra is bigger, redder and a little more demanding. Here's which shoal suits your tank.
The quick verdict
If you want the easiest, hardiest option for a general community, the neon tetra is the safe pick — it copes with neutral water and any mature tank. If you can offer warm, soft, acidic water in a well-established, planted tank, the cardinal tetra rewards you with more red and a bigger body. Both need a shoal of six or more.
| Neon tetra | Cardinal tetra | |
|---|---|---|
| Care level | Easy | Intermediate |
| Min tank size | 54 L / 14 gal | 60 L / 15 gal |
| Temperament | Peaceful | Peaceful |
| Adult size | 3–4 cm | 4–5 cm |
| Water | pH 5.5–7.0, adaptable | pH 4.5–6.5, soft & warm |
| Best for | Hardy first shoal, cooler tanks | Soft-water tanks, maximum colour |
The real differences
The obvious one is the red band: full-length on a cardinal, half-length on a neon. Beyond looks, it comes down to water. Neons are happy at 22–26 °C and pH up to 7.0, which is why they thrive in ordinary tap-water community tanks. Cardinals prefer 24–28 °C and genuinely soft, acidic water (pH 4.5–6.5), and they dislike the swings of a new setup — hence the intermediate rating. Cardinals are also marginally larger and shorter-lived (4–5 years vs 5–8 for neons).
Which should you buy?
Our pick
Pick the neon tetra if this is an early tank, your water is neutral-to-hard, or you just want a bomb-proof shoal that runs cooler. Pick the cardinal tetra if you keep a mature, soft-water planted tank and want the deepest red. Read the full neon tetra care guide and cardinal tetra care guide, or plan a home in our best nano aquarium picks.
Frequently asked questions
What is the difference between a neon and a cardinal tetra?
The red stripe. On a cardinal tetra the red runs the full length of the body; on a neon it only covers the rear half. Cardinals are also slightly larger (4–5 cm vs 3–4 cm) and want warmer, softer, more acidic water, which makes them a touch more demanding.
Which is easier for a beginner, neon or cardinal tetra?
The neon. It is rated easy, tolerates neutral water down to pH 7.0 and stays hardy in any mature, cycled tank. Cardinals are intermediate — they prefer warmer, soft, acidic blackwater conditions and a truly settled tank, so they suit a keeper with a little experience.
Can neon and cardinal tetras be kept together?
Yes. They are peaceful, similar in size and mix happily in the same soft-water shoal, though each schools more tightly with its own kind. Keep at least six of each so both feel secure.
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