Fish Compatibility Checker
Find compatible fish for your aquarium. Our checker helps you choose peaceful tank mates.
Fish Compatibility Basics
Successful community tanks require matching temperament, water parameters, and size. Aggressive fish, temperature mismatches, and size differences are the three most common causes of tank mate failure.
| Fish | Temp (F) | pH | Temperament | Min Tank |
|---|---|---|---|---|
| Betta | 76-82 | 6.5-7.5 | Semi-aggressive (males) | 5 gal |
| Goldfish | 65-72 | 7.0-8.0 | Peaceful | 20 gal |
| Neon Tetra | 72-78 | 6.0-7.0 | Peaceful (schooling) | 10 gal |
| Guppy | 72-82 | 7.0-8.0 | Peaceful | 10 gal |
| Angelfish | 76-84 | 6.0-7.5 | Semi-aggressive | 30 gal |
| Oscar | 74-81 | 6.0-8.0 | Aggressive (predator) | 75 gal |
What makes fish incompatible?
Temperature mismatch (goldfish need cold water, tropicals need warm), size difference (large fish eat small fish), aggression (bettas attack flashy fins, oscars eat anything that fits in their mouth), and water chemistry (African cichlids need hard alkaline water, discus need soft acidic).
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