As fish grow in length, they increase in weight. The relationship between weight and length is not linear. The relationship between length (L) and weight (W) can be expressed as: W = aL^b\!\, where W is the whole body wet weight in grams and L is the length in centimeters; the factor 100 is used to bring K close to a value of one.

Fulton's condition factor is used as a basis for comparison to assess the health of an individual or group of fish.

Generally, fish that are heavier than the standard weight for their length are considered healthier, having more energy reserves for normal activities, growth and reproduction.

Generally, fish that are less than the standard weight for their length are considered in poor health, having less energy reserves for normal activities, growth and reproduction. Possible reasons for a poor Fulton's condition factor maybe the lack of food/prey, increased competition, habitat unsuitability or an infection.