Pet fish
How long do pet fish live?
Betta, goldfish, community fish and koi do not share one lifespan number. Use group and age for planning, then review water and health signals.
Care considerations
Water testing and stable cycling matter for welfare, but this calculator keeps them in the notes instead of turning them into years.
Filtration, oxygenation and temperature should match the fish group and tank size.
Compatibility and crowding risk deserve review before adding more fish.
Feeding and quarantine routines help prevent problems, but are not reliable lifespan coefficients.
Visible illness signs can make the general range unsuitable; use qualified fish-health advice for individual planning.
Estimated lifespan
This estimate is for planning, not a medical prognosis. Fish group and age change the lifespan number; water, tank and health fields shape the notes.
For planning and education only. It does not replace an aquatic veterinarian or qualified fish-health advice. Seek help for gasping, clamped fins, spots, wounds, bloating, swimming changes or sudden losses.