Dynamic energy budget (DEB; also known as Kooijman–Metz DEB) theory is a well-tested framework for modelling energy acquisition, and for describing vital rates at which organisms acquire and use energy, such as for growth and reproduction. The coupling of a DEB with an agent-based model (generating a DEB- ABM) enables examination of the effects of environmental change at a population-level on a species to be examined. The present study applied a DEB-ABM to the Japanese anchovy Engraulis japonicus. The DEB-ABM accurately captured energy acquisition and allocation throughout the anchovy lifecycle (egg, yolk sac larva, exogenous feeding larva, juvenile, and adult) and predicted how individual-level processes affect energy dynamics at higher levels of biological organization. We estimated primary model parameters (e.g., energy conductance, ὺ; allocation coefficient, κ; and volume-specific somatic maintenance, [ṗM]), and for a 5-year simulation, calculated a mean population growth rate (rp) of 3.4 year−1. When DEB theory is combined with an ABM, the combined model describes the dynamics of a population of individuals, where each individual follows an energy budget model. Predicted demographic rates (growth, survival, reproduction) fall within observed ranges, fit average recorded values, and captured known seasonal trends. The DEB-ABM correlated intrinsic and density-independent population growth rates, and may be useful for predicting the metabolic responses of individuals or populations to environmental change.