We examined juvenile growth of five species of Daphniidae raised at several food levels. For each species, an exponential model with a species‐specific exponent accurately described the weight gain of preadult instars. This finding indicates that weight‐specific net production within a species is constant throughout juvenile development; early and late instars are equal in exploitative ability.Among clones born at different body weights, specific net production depended on food level. At high food levels, larger bodied animals displayed greater exploitative ability (larger exponents). However, as food level was lowered, specific net production of large‐bodied animals was depressed more severely than that of small‐bodied animals. At the lowest food level, smaller bodied animals exhibited greater exploitative ability.