An introduction to modeling is presented. The basic concepts of systems and models and various types of models and their use in research and in management are described. Guidelines for modeling aquaculture systems are presented: empirical models for the analysis of multivariate datasets and theoretical models based on knowledge of the various processes underlying a system. Examples of two modeling approaches to the production of Nile tilapia (Oreochromis niloticus) in ricefields are given in an appendix.