Sailfin molly populations often experience a midsummer slump in reproduction, and it has been suggested that this slump is caused by food shortage. A food supplementation experiment on a natural population of mollies was done in 1983. Excess food did not directly affect the fecundity of females in the field. A laboratory experiment was designed to determine the food level on reproduction in females. Ration had the greatest effect on somatic condition and growth, indirectly influencing fecundity. Two explanations for this strategy are suggested. A significant difference in brood size and size of young was observed between the field and lab broods at all ration levels. The possibility of plasticity being an integral component of the sailfin molly’s life history strategy is discussed
