Over the last decade, a range of studies have demonstrated that various fitness-related behaviours are vulnerable to disruption induced by various contaminants of emerging concern (CECs) and legacy pollutants. However, the behavioural responses of animals when exposed to pollutants/contaminants are rarely included in discussions about the regulation of chemicals. Thus, to improve our understanding of the opportunities and challenges for behavioural ecotoxicology, this chapter presents a synthesis of the endpoints and experimental procedures used to evaluate the behavioural response of Nile tilapia (Oreochromis niloticus – a non-conventional species in ecotoxicology) to different CECs and legacy pollutants. By focusing on the methodological possibilities to be used in evaluating the behaviour of this Neotropical species, we shed light on the feasibility and reasonableness of using this animal model as a complement or alternative to the use of model species traditionally used in toxicology.