Our view of nonhuman animals has been influenced by a priori claims about the capacities of animals. Animals such as fish are excluded from the moral community because they lack intentionality as a basic capability. Here, animals like fish do not have intentional mental states, that is, their mental states lack content or 'aboutness'. The upshot is that animals like fish cannot be conscious. In recent decades, animal ethologists and philosophers alike have appealed to a posteriori arguments that attempt to debunk the view that intentionality and thus, conscious states, are exclusively human capabilities. Appeals to the evolution of complex cognitive skills per fitness, in conjunction with evidence of their social and environmental intelligence, serve to motivate the belief that animals, too, lead intentional lives. A central premise here is that conscious intentional states are a precondition of learning. This paper argues that 'aboutness' or mental content vis a vis mental representations can also be discovered in fish. Representational content can be ascribed in fish when we consider how beliefs and desires, from the fish's point of view, influence behaviour. As will be argued, the relationship between beliefs, desires and mental representations as they relate to learning and manifested through competition over access to mates, cooperation for hunting, information gathering, symbiotic cleaning, and foraging in teleost fish, will be discussed. After a discussion of the influential arguments' of philosophers Descartes and Donald Davidson, this paper will consider the merits of an a posteriori way of thinking about mind in animals. Building on Dennett's 'intentional stance' towards the behaviour of animals, it will be argued that inferring the presence of intentionality or 'aboutness' is the most plausible explanation behind learning in certain fish. The implications for the moral status and welfare of fish will be discussed briefly thereafter.