Can cardinal tetras and fancy goldfish live together?
No
Cardinal tetras and fancy goldfish should not share a tank.
Why
- Cardinal tetras need at least 73°F (23°C), but fancy goldfish should stay at or below 72°F (22°C). No temperature suits both.
- Their pH ranges only meet at 7.0, which leaves no margin.
- Goldfish are slow, messy, cold-water fish. They do best in a tank with other goldfish.
What each one needs
| Cardinal tetra | Fancy goldfish | Both | |
|---|---|---|---|
| Temperature | 73–84°F (23–29°C) | 65–72°F (18–22°C) | No overlap |
| pH | 5.0–7.0 | 7.0–8.0 | 7.0–7.0 |
| Minimum tank | 20 gal (76 L) | 20 gal (76 L) | 20 gal (76 L) |
| Keep at least | 6 | 1 | |
| Adult size | 2 in (5.1 cm) | 7 in (17.8 cm) |