What size tank do cardinal tetras need?
At least 15 gallons (57 liters) for a group of 6. The smallest standard tank that works is the 15 gallon. A bigger tank is always easier to keep stable. We give the size for an adult fish in a proper group, because the small fish in the shop will grow. Scientific name: Paracheirodon axelrodi.
How many cardinal tetras in each tank size?
This is how many each standard tank carries comfortably if cardinal tetras are the only fish in it. Share the tank with other species and the number goes down.
| Tank | How many cardinal tetras |
|---|---|
| 5 gallon | Too small |
| 10 gallon | Too small |
| 20 gallon long | up to 14 |
| 29 gallon | up to 20 |
| 40 gallon breeder | up to 28 |
| 55 gallon | up to 39 |
| 75 gallon | up to 53 |
| 125 gallon | 60 or more |
Check cardinal tetras against your own tank and other fish
Good to know
- Keep at least 6. Alone or in twos and threes, cardinal tetras hide, stop eating well, or pick on each other.
Tank mates for cardinal tetras
These animals like the same water, are a safe size, and have a temper that fits. It is a match on paper: always watch new tankmates for the first week.
- Honey gourami
- Threadfin rainbowfish
- Marbled hatchetfish
- Sterba's corydoras
- Clown pleco
- Kuhli loach
- Sparkling gourami
- Pearl gourami
Poor matches
- Guppy: They need different water: Cardinal tetra likes a pH of 4.5–7, guppy likes 7–8.2.
- Fancy goldfish: Goldfish do best with other fancy goldfish.
- Oscar: Oscar is aggressive and will bully or kill peaceful fish such as cardinal tetra.
- Molly: These fish do not share a comfortable pH range. Choose fish from similar water.
Questions and answers
What size tank do cardinal tetras need?
At least 15 gallons (57 liters) for a group of 6. The smallest standard tank that works is the 15 gallon. A bigger tank is always easier to keep stable.
How many cardinal tetras should be kept together?
At least 6. Cardinal tetras are social animals and only behave naturally in a group. More is better if the tank has room.
Can cardinal tetras live in a 10 gallon tank?
No. Cardinal tetra needs at least 15 gallons (57 liters).
What temperature do cardinal tetras need?
75–84 °F (24–29 °C), with a pH of 4.5–7. In most homes that means a heater.
Can cardinal tetras live with a betta?
Usually, yes, in a tank of 15 gallons (57 liters) or more. They like the same water: 75–82 °F (24–28 °C). Every betta has its own temper, so watch closely for the first week and have a spare tank ready.
More fish
Adult size, tank size and water ranges follow the mainstream care consensus (Seriously Fish species profiles and FishBase maximum lengths). Where sources differ we use the more cautious figure. Stocking numbers come from our stocking calculator.