Fish comparison
Bolivian Ram vs Cardinal Tetra
How the Bolivian Ram and Cardinal Tetra compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Bolivian Ram vs Cardinal Tetra
The Bolivian Ram 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 23 to 27 °C and pH 6.5 to 6.5, so a single tank can suit either one. The Bolivian Ram 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 Cardinal Tetra needs less room to feel settled; give the Bolivian Ram 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
- Bolivian Ram22–27 °C
- Cardinal Tetra23–27 °C
pH
- Bolivian Ram6.5–7.5
- Cardinal Tetra4.5–6.5
Hardness
- Bolivian Ram5–14 dGH
- Cardinal Tetra1–6 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 |  FishBolivian RamMikrogeophagus altispinosus |  FishCardinal TetraParacheirodon axelrodi |
|---|---|---|
| Category | Fish | Fish |
| Origin | Amazon basin, Bolivia and Brazil | Upper Orinoco and Rio Negro basins |
| Family | Cichlidae | Characidae |
| Temperature | 22–27 °C | 23–27 °C |
| pH | 6.5–7.5 | 4.5–6.5 |
| Hardness (dGH) | 5–14 | 1–6 |
| Flow rate | Low to Medium | Low |
| Min tank | 100 L | 75 L |
| Adult size | 7–8 cm | 4–5 cm |
| Difficulty | 2 / 5 | 3 / 5 |
| Lifespan | 4–6 yrs | 4–6 yrs |
| Diet | Omnivore | Omnivore |
| Water column | Mid to Bottom | Mid |
| Schooling | No (pair or small group) | Yes |
| Plant safe | Yes | Yes |
| Shrimp safe | Risky with dwarf 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 Bolivian Ram and Cardinal Tetra together?
Yes. Their temperature and pH ranges overlap around 23 to 27 °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 Bolivian Ram or the Cardinal Tetra?
The Bolivian Ram is the easier of the two, closer to beginner-friendly, while the Cardinal Tetra leans middle-of-the-road.
Do Bolivian Ram and Cardinal Tetra need the same water?
Close to it. Aim for 23 to 27 °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 Bolivian Ram and the Cardinal Tetra?
Temperament is the big one. The Bolivian Ram is territorial when breeding and the Cardinal Tetra is peaceful, which changes who you can house them with.