Tropical fish present some of the best examples of how new species evolve and how complex ecological communities are maintained. Their study has generated important new ideas on the roles of ecology and behaviour in the evolution of species and communities. This book brings together for the first time the results of widely scattered research on fish in tropical rivers, lakes and seas, research that has been stimulated by the splendid opportunities to observe the behaviour of fish in their natural habitats in the clear warm waters. The book opens with an overview of the ecology of tropical freshwater and marine environments and their associated fish faunas, and then presents a number of freshwater studies drawn from the African, South American, Asian and New Guinea tropics. Special consideration is given to the new man-made lakes which have provided large-scale experiments on the change of riverine fish communities to lacustrine ones, and to the great lakes of East Africa for examples of recent species evolution.