Existing evidences showing the effect of food quality (stoichiometry) on the efficiency of energy and materials transfer from autotrophs to herbivores were mainly gained from studies in the lab. Here, we investigate whether food quality and stoichiometric mismatch between food and consumers can impact on growth rates of herbivorous copepods, using field data in the East China Sea. We use carbon-to-nutrient ratios of particulate organic matter and two zooplankton community size fractions (nauplii and copepodits) to represent stoichiometry of phytoplankton and copepods respectively, and measure copepod weight-specific growth rates using the artificial cohort method. We remove temperature and body size effects on growth rates according to the Metabolic Theory of Ecology a priori. Our results contradict the typical concept of stoichiometric homeostasis but show greater variation and higher values of C:N in copepods, deviating upward from the classic Redfield ratio. Surprisingly, growth rates of both size fractions were not affected by food quality. Rather, growth rates of copepodites increased significantly with the increasing stoichiometric mismatch (i.e. increasing discrepancy between C:N of copepodite and C:N of phytoplankton).