Calculate how old your fish is in human years. Different fish species have vastly different lifespans and aging rates.
Fish ages vary dramatically by species. A guppy lives only 2â3 years while a koi can live 30+ years. This calculator uses species-specific ratios based on aquarium research to convert fish age to the human equivalent.
Lifespan varies 10x+ between fish species â a guppy vs. a koi age at vastly different rates.
Age impacts tank size, water parameters, and setup. Older fish need stable, mature environments.
Fry, juvenile, and adult fish have different nutritional needs. Feeding incorrectly can stunt growth.
Older fish need more attentive care and disease prevention. Knowing their age helps you spot age-related issues.
| Category | Species | 1st Year (Human) | Per Extra Year | Max Fish Years |
|---|---|---|---|---|
| Short | Guppy, Molly, Platy, Neon Tetra, Danio, Killifish, Rasbora | 30 | 20 | 3â5 |
| Medium-Short | Betta, Swordtail, Gourami, Rainbowfish | 25 | 15 | ~5 |
| Medium | Goldfish (Common), Angelfish, Corydoras, Loach | 15 | 8 | 10â15 |
| Medium-Long | Goldfish (Fancy), Oscar, Plecostomus, Clown Loach | 12 | 6 | 15â20 |
| Very Long | Koi, Discus, Cichlid (African), Cichlid (S. American) | 8 | 4 | 25â30 |
This calculator uses research-backed species-specific ratios. However, individual fish aging varies based on genetics, diet, water quality, and tank conditions. Use the results as a general guide.
Different species have vastly different metabolic rates and maximum lifespans. A guppy lives 2â3 years while a koi can reach 30+. The ratio of fish years to human years must account for these differences.
If you didn't raise your fish from birth, check with the breeder or pet store. Size can be a rough indicator, but it's unreliable since growth depends on tank size, diet, and water quality.
This calculator is designed for common freshwater aquarium species. Saltwater fish have different aging rates that may not match these formulas.
It's a comparison tool to help owners understand their fish's life stage relative to human development. It doesn't mean fish experience time the same way humans do.