About StockMyTanks
StockMyTanks.com is a free tool that helps aquarium hobbyists check whether their fish can live together safely. We built it because we got tired of getting conflicting advice on forums and wanted a single, data-driven resource.
How Our Compatibility Data Works
Our compatibility engine checks multiple factors for every fish pairing:
- Temperature range overlap — Can both species thrive at the same temperature?
- pH compatibility — Do they need similar water chemistry?
- Temperament matching — Will an aggressive fish bully a peaceful one?
- Size ratio — Is one fish big enough to eat the other?
- Swim level — Do territorial fish compete for the same space?
- Known pairings — Specific fish combinations that are known to work well (or not) in practice, beyond what the numbers alone suggest.
A Note on Accuracy
Fish compatibility is not black and white. Individual fish have personalities, and tank setup matters enormously. A pairing that works in a 75-gallon planted tank might be a disaster in a bare 20-gallon. Our tool gives you a strong starting point, but always:
- Research specific species from multiple sources
- Have a backup plan (extra tank or divider) when introducing new fish
- Watch for signs of stress or aggression after adding fish
- Ask experienced fishkeepers in your local community
Privacy
StockMyTanks runs entirely in your browser. We don't track you, sell your data, or require an account. Your saved tanks are stored in your browser's local storage — if you clear your browser data, they're gone.
Contact
Found an error in our fish data? Have a suggestion? We'd love to hear from you at hello@stockmytanks.com.