First Hour
Little risk for most tanks if outage ends soon.
Do not feed — waste accumulates without filtration.
Battery-powered air pump if stocking is heavy.
2-6 Hours
Oxygen depletion becomes real, especially in warm heavily stocked tanks.
Battery air pump essential.
Surface splash from a manual pour every 30 minutes helps.
6-24 Hours
Temperature drops. Wrap tank in blankets for insulation.
Hot water bottles float inside or outside bag to maintain heat.
Bacterial die-off starts in filter. Prime filter media back into tank water.
24+ Hours
Plan to move fish to a generator-powered space or friend tank.
Power station or generator rated 500W runs most tanks indefinitely.
Preparedness Kit
Battery air pump with spare batteries.
Manual thermometer.
Seachem Stability (bacteria refresher).
Prime for bacteria-loss ammonia protection.