Previous studies have shown that mummichogsFundulus heteroclitusinhabiting Piles Creek, a polluted tributary of the Arthur Kill in Linden, New Jersey, do not grow as well as conspecifics from more pristine habitats. Our study was designed to investigate whether or not reduced prey capture ability contributes to the impaired growth in the pollution-stressed population. When presented with juvenile guppiesPoecilia reticulataas food, the mummichogs from Piles Creek did not capture them as effectively as did fish from a reference site in Southampton, New York. Furthermore, field-collected specimens from the reference site showed both greater body weight for a given length and fuller stomachs than Piles Creek specimens. Gut contents of Piles Creek fish consisted primarily of detritus and sediments, whereas those of the reference fish were largely crustacean remains. Thus, the reduced growth in the Piles Creek population may be due in part to reduced feeding rate.