This paper proposes to identify matters to be considered when modelling anaerobic digestion processes of fish waste. The design of the model takes into account the specific features of fish waste as substrate. Previous research shows that the anaerobic digestion and co-digestion of fish waste has significant potential for biomethane production – from 0.2 up to 0.9 CH4 m3/kg VS added. Generally, anaerobic digestion processes are modelled in two ways – using both micro-organism growth kinetics and chemical reactions in the system. The production of biogas using anaerobic digestion involves the use of different substrates with different properties. However, waste from fish processing poses distinct technological problems because it releases high levels of ammonia when digested. This can later reduce or inhibit the digestion of substrates.