Fish comparison
Siamese Fighting Fish vs Cardinal Tetra
How the Siamese Fighting Fish and Cardinal Tetra compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Siamese Fighting Fish vs Cardinal Tetra
The Siamese Fighting Fish and the Cardinal Tetra come up together a lot when people are choosing a fish, and they are close enough to weigh side by side. Both are happy somewhere around 24 to 27 °C and pH 6 to 6.5, so a single tank can suit either one. The Siamese Fighting Fish is the more forgiving of the two, which matters if this is an early tank, while the Cardinal Tetra rewards a bit more attention. If tank space is tight, the Siamese Fighting Fish needs less room to feel settled; give the Cardinal Tetra the nod when you have the litres to spare.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
1 note
Temperature
- Siamese Fighting Fish24–28 °C
- Cardinal Tetra23–27 °C
pH
- Siamese Fighting Fish6–7.5
- Cardinal Tetra4.5–6.5
Hardness
- Siamese Fighting Fish3–15 dGH
- Cardinal Tetra1–6 dGH
What to plan for
- Cardinal Tetra schools, stock at least 8You've planned for 1 cardinal tetra. Cardinal Tetra need a group of at least 8 to feel safe and shoal naturally, below that they're stressed and lose colour. Dial up the count, or remove the species.
Full attributes
Every parameter, side by side| Parameter |  FishSiamese Fighting FishBetta splendens |  FishCardinal TetraParacheirodon axelrodi |
|---|---|---|
| Category | Fish | Fish |
| Origin | Mekong basin, Thailand and Cambodia | Upper Orinoco and Rio Negro basins |
| Family | Osphronemidae | Characidae |
| Temperature | 24–28 °C | 23–27 °C |
| pH | 6.0–7.5 | 4.5–6.5 |
| Hardness (dGH) | 3–15 | 1–6 |
| Flow rate | Very low | Low |
| Min tank | 20 L | 75 L |
| Adult size | 6–7 cm | 4–5 cm |
| Difficulty | 2 / 5 | 3 / 5 |
| Lifespan | 3–5 yrs | 4–6 yrs |
| Diet | Carnivore | Omnivore |
| Water column | All | Mid |
| Schooling | No | Yes |
| Plant safe | Yes | Yes |
| Shrimp safe | No (adult bettas pick off shrimp) | Mostly (may eat shrimplets) |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Siamese Fighting Fish and Cardinal Tetra together?
Yes. Their temperature and pH ranges overlap around 24 to 27 °C and pH 6 to 6.5, so one set of water conditions keeps both comfortable. Match group sizes and cover the usual planted-tank basics and they share a tank fine.
Which is easier to keep, the Siamese Fighting Fish or the Cardinal Tetra?
The Siamese Fighting Fish is the easier of the two, closer to beginner-friendly, while the Cardinal Tetra leans middle-of-the-road.
Do Siamese Fighting Fish and Cardinal Tetra need the same water?
Close to it. Aim for 24 to 27 °C and pH 6 to 6.5 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Siamese Fighting Fish and the Cardinal Tetra?
Temperament is the big one. The Siamese Fighting Fish is territorial when breeding and the Cardinal Tetra is peaceful, which changes who you can house them with.