Fish condition calculator
These numbers are typed in. Trace your pond once and every calculator uses its measured volume and depths.
Measure my pondHow it works
Wr compares one fish against a standard for its whole species. To judge a pond, average ten or more fish from the same size range instead of relying on a single weighing.
Standard weight comes from the published length-weight equation for the species.
Each standard weight (Ws) equation gives the 75th percentile weight for a fish of that length across the species' range. They come from Anderson and Neumann, Fisheries Techniques (1996), and the papers it compiles. Each equation has a minimum length and does not hold for shorter fish. Length categories (stock, quality, preferred, memorable, trophy) follow Gabelhouse (1984).
A Wr of 90 to 110 means the fish is in good condition. If many fish come in under 80, it points to too little food for the number of predators, or a crowded year class. Over 110 means the fish is well fed. Condition changes with the season and with spawning, so compare fish sampled at the same time of year.
Practitioner discussion: Pond Boss forum threads Relative Weight Charts and Fish Weight Calculator.
Want the precise number?
Type your measurements in above for a quick estimate. For the real volume, trace your pond on a photo or satellite image and set its depths. PondTools measures the actual outline, so dosing, liner and pump sizes come out right.
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