Live Well Capacity Calculator

This calculator sizes a live well around total fish biomass (number of fish times average weight) rather than fish count alone, since it's the combined weight that determines oxygen demand and waste production. Minimum capacity uses the simplest rule of thumb — 1 gallon of water per pound of fish — as an absolute floor, while recommended capacity applies a more generous 1.75 gallons per pound and then layers on two multipliers: a temperature factor and a duration factor. The temperature multiplier climbs sharply above 70°F (1.2× at 70–75°F, up to 1.8× above 80°F) because warm water holds substantially less dissolved oxygen than cool water, and drops to 0.85× below 55°F where fish are more dormant and less stressed by confinement. The duration multiplier adds 8% capacity for every hour beyond a 4-hour baseline, since fish continuously consume oxygen and produce ammonia waste the longer they're held — an 8-hour tournament day needs meaningfully more capacity than a quick 2-hour outing.

Aeration rate (in gallons per hour) and oxygen demand (in mg/hour) both scale with the same total fish weight and temperature multiplier, giving you two different lenses on the same underlying oxygen requirement — one sized to your pump, one to the fish's actual physiological need. Water change frequency shortens as temperature rises (down to every 8 minutes above 75°F) and shortens further when holding more than 5 fish, since more bodies in the same water deplete oxygen and build up waste faster. These are planning targets based on typical bass physiology — actual mortality risk also depends on handling stress, water clarity, and how aggressively fish were fought before landing, none of which this calculator measures.