In this study, we quantify the onset of feed assimilation by channel catfish using stable isotopes of carbon (δ13C) and nitrogen (δ15N). In a recent pond experiment at the Hebron State Fish Hatchery, Ohio, USA, Filbrun et al. (2013) showed that the provided dry feeds were enriched relative to naturally occurring zooplankton and insects by about 4–6‰ in δ13C and 4–7‰ in δ15N