Fish comparison
Cardinal Tetra vs Peacock Gudgeon
How the Cardinal Tetra and Peacock Gudgeon compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Cardinal Tetra vs Peacock Gudgeon
The Cardinal Tetra and the Peacock Gudgeon 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 23 to 26 °C and pH 6.5 to 6.5, so a single tank can suit either one. The Peacock Gudgeon 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 Peacock Gudgeon needs less room to feel settled; give the Cardinal Tetra the nod when you have the litres to spare.
Group compatibility overview
Good fit
Workable as-is, only minor advisories to plan around.
1 warning · 2 notes
Temperature
- Cardinal Tetra23–27 °C
- Peacock Gudgeon22–26 °C
pH
- Cardinal Tetra4.5–6.5
- Peacock Gudgeon6.5–7.5
Hardness
- Cardinal Tetra1–6 dGH
- Peacock Gudgeon5–15 dGH
What to plan for
- Narrow pH overlapTarget pH is 6.5–6.5. Test weekly; use buffered substrate or remineraliser to keep it stable.
- 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.
- 67% of your fish swim in the midHeavy concentration in a single zone. Spreading stocking across all three levels makes the tank read fuller for the same bioload.
Full attributes
Every parameter, side by side| Parameter |  FishCardinal TetraParacheirodon axelrodi |  FishPeacock GudgeonTateurndina ocellicauda |
|---|---|---|
| Category | Fish | Fish |
| Origin | Upper Orinoco and Rio Negro basins | Papua New Guinea |
| Family | Characidae | Eleotridae |
| Temperature | 23–27 °C | 22–26 °C |
| pH | 4.5–6.5 | 6.5–7.5 |
| Hardness (dGH) | 1–6 | 5–15 |
| Flow rate | Low | Low to Medium |
| Min tank | 75 L | 60 L |
| Adult size | 4–5 cm | 5–7 cm |
| Difficulty | 3 / 5 | 2 / 5 |
| Lifespan | 4–6 yrs | 4–5 yrs |
| Diet | Omnivore | Carnivore |
| Water column | Mid | Mid to bottom |
| Schooling | Yes | No (loose group) |
| Plant safe | Yes | Yes |
| Shrimp safe | Mostly (may eat shrimplets) | Adults only (eats shrimplets) |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Cardinal Tetra and Peacock Gudgeon together?
Yes. Their temperature and pH ranges overlap around 23 to 26 °C and pH 6.5 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 Cardinal Tetra or the Peacock Gudgeon?
The Peacock Gudgeon is the easier of the two, closer to beginner-friendly, while the Cardinal Tetra leans middle-of-the-road.
Do Cardinal Tetra and Peacock Gudgeon need the same water?
Close to it. Aim for 23 to 26 °C and pH 6.5 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 Cardinal Tetra and the Peacock Gudgeon?
Space. The Cardinal Tetra wants about 75 litres minimum and the Peacock Gudgeon around 60, so tank size can settle it.