Fish behaviour

Behaviour involves reacting to stimuli and may be innate (colour change) or include input via cognition (learning, memory). Understanding the complex behaviour of some fish, as in interaction with conspecifics, potential prey or predators, may require consideration of neurobiology and endocrinology. Whereas fish may show behaviours associated with tetrapods (play, sleep), some of their behaviour follows a preset pattern, for example in feeding and reproduction. Communication between fish depends on cues such as colour, sound, electroception or pheromones. Long-term behaviour includes migration and territoriality, with schooling a group phenomenon. Within the brain a neuropil may indicate a region capable of memory, in fish it is abundant in the optic tectum with up to 15 laminae (layers), with some in the olfactory bulb; however, the laminated cerebral cortex of mammals is lacking. Current research includes the role of engrams in memory and the use of zebrafish as models.