Cognitive abilities underpin almost every animal behaviour and allow them to gather, store, process, and use information essential for survival and reproduction. Great variation in cognitive abilities exists not only between different species, but even across individuals from the same population. This variation suggests that the evolution of cognition involves multiple factors. Cognitive abilities, their adaptive value, and their biological predictors remain poorly understood in wild animals and are particularly overlooked in fish. In this seminar, I will first talk about how we can objectively quantify fish cognition, including memory, learning, and self-control. I will then present experimental studies exploring how various traits and environmental factors impact cognition, from sex and age of the fish, to pharmacological pollution and climate change. Lastly, I will discuss selection on cognitive abilities in fish, its role in survival and reproduction.