Models are important tools to address sustainability challenges associated with developing aquaculture at farm, regional and global scales. Farm-scale models (FSMs), which are integrated mathematical models developed to simulate farm operations, can quantify energy, mass or economic input flows and predict a variety of outputs such as fish biomass, waste and by-products. The variety of farming systems, equations available to build the models, and objectives of applications and intended users has resulted in the publication of wide range of FSMs. We performed a narrative review of 36 fish FSMs published from 1985–2021 to address several questions: Can the main characteristics of these models be defined? How do the farming system studied and the objectives of the study influence model development? What are the main modelling techniques available to simulate the main processes of a fish farm, and what are their advantages and disadvantages? How can FSMs help address sustainability challenges of aquaculture? This review discusses advances, limitations and future lines of research related to FSMs to help select existing models, or develop new ones, that are suitable for their intended use and users. The article is structured according to the main steps of the modelling process: (i) definition of scope and objectives; (ii) process formulation and model selection at individual, cohort and farm levels; (iii) implementation and evaluation; and (iv) applications (e.g. precision fish farming, IMTA modelling, supporting spatial management, life cycle assessment). At each step, recommendations are provided and research needs are stated.