Work out fish growth rate instantly with clear inputs, formula shown and shareable results.
Specific growth rate is the exponential growth constant, (ln final weight - ln initial weight) / days x 100, and is the standard way to compare growth between fish of different sizes. Average daily gain is the simple arithmetic rate, and dividing feed used by the gain gives the FCR for the period.
Specific growth rate
SGR (%/day) = (ln W_final - ln W_initial) / days x 100
Feed conversion
FCR = feed consumed / weight gain
A 50 g fish gaining 2 g/day is growing far faster in relative terms than a 500 g fish gaining the same. SGR normalises for size so growth can be compared across stages.
1.0-1.4 for well-managed tilapia and catfish on pelleted feed, 1.5-2.0 for carp polyculture, and above 2.5 indicates overfeeding, poor water quality or disease.