AquaGauge

Aquarium answers, backed by real tanks

Free, modern calculators and stocking data — every number grounded in real data from hundreds of real aquariums, not guesswork or the old inch-per-gallon myth.

Stocking calculator → Volume calculator
– stocked –
    Pick a tank size, then drag the slider up to stock it ↑

    Got your own tank and fish in mind? Run your exact setup — any size, any species.

    Plan your own tank in the calculator →

    Calculators

    Stocking calculator

    Add your fish + tank size → live stocking %, filtration % and compatibility warnings.

    Volume calculator

    Tank dimensions → gallons, litres and filled weight, for any shape.

    Water change calculator

    Current vs target nitrate → exact % and gallons to change, split into safe steps.

    Coming next: heater wattage, filter turnover and dosing calculators.

    Backed by real-tank data, not guesswork

    Aggregated from 375+ real freshwater tanks shared on Reddit (r/Aquariums, r/PlantedTank, r/bettafish, r/shrimptank) where keepers reported readings. Bars show the interquartile range; the tick is the median. How we collect this.

    Temperature 78°F · range 65–86°F · n=189
    64°F88°F
    pH 7.4 · range 4–9 · n=375
    59
    Nitrate 5 ppm · range 0–120 ppm · n=375
    0 ppm80 ppm

    ⚠️ 31% of tanks where the keeper posted an ammonia reading showed a detectable (>0 ppm) level — a sign of an uncycled or struggling tank. (Readings skew toward keepers troubleshooting a problem, so treat this as a worst-case among posted tanks.)

    Fish species & care guides

    Data-backed care hubs: tank size, water, diet, and compatible tankmates for each species.

    Betta Fish Betta Fish Guppy Guppy Neon Tetra Neon Tetra Cherry Shrimp Cherry Shrimp Corydoras Catfish Corydoras Catfish

    Stocking guides

    What Fish Can Live With Bettas? What Fish Can Live With Bettas? Betta Tank Water Parameters (Temp + pH) Betta Tank Water Parameters (Temp + pH) How Often Should You Change Aquarium Water? How Often Should You Change Aquarium Water? What Is the Ideal pH for a Freshwater Aquarium? What Is the Ideal pH for a Freshwater Aquarium? How Many Fish Can You Keep in a 10-Gallon Tank? How Many Fish Can You Keep in a 10-Gallon Tank? How Many Guppies Can You Keep in a 10-Gallon Tank? How Many Guppies Can You Keep in a 10-Gallon Tank? How Many Fish Can You Keep in a 20-Gallon Tank? How Many Fish Can You Keep in a 20-Gallon Tank? What Size Aquarium Do You Actually Need? What Size Aquarium Do You Actually Need? What Size Tank Does a Betta Need? What Size Tank Does a Betta Need? How Many Shrimp Can You Keep Per Gallon? How Many Shrimp Can You Keep Per Gallon? What Size Tank Do Shrimp Need? What Size Tank Do Shrimp Need? 5-Gallon vs 10-Gallon Betta Tank 5-Gallon vs 10-Gallon Betta Tank Ammonia & Nitrate Levels for Betta Fish Ammonia & Nitrate Levels for Betta Fish How Many Neon Tetras in a 10-Gallon Tank? How Many Neon Tetras in a 10-Gallon Tank?

    How-to guides

    How to Lower Nitrates in a Fish Tank How to Lower Nitrates in a Fish Tank

    All guides →

    Why AquaGauge

    The aquarium niche is split between one powerful-but-ancient stocking tool and content sites that cite no sources and name no authors. AquaGauge combines both halves: a fast, mobile, visual calculator wrapped in data-cited, transparently-sourced answers — including aggregated stats from real hobbyist tanks. See our methodology.