Since two years, the ichthyofauna of Gazi Bay, Kenya is under intense investigation. According to Snedaker (1978) more than 90% of the fish species in tropical coastal regions can be found at mangrove and seagrass habitats, during one or more periods in their life cycle. These habitats appear essential for the completion of their cycle. Seagrass fields for example play a crucial role as nurseries for many fish species: in general, it can be assumed that all species were caught at their juvenile stage. Also the surrounding habitats (corals, mangroves) seem to have an important influence on the productivity and diversity of a community. These communities on their turn serve as feeding grounds for the larger carnivores. It is clear that we are dealing with a complex ecosystem in which each part has an important function. The thesis of De Troch (1995) and Boone (1996) already imply the great species diversity of the fish fauna of the tropical seagrass fields. However , they used different sampling techniques: De Troch used a purse seine nets, and Boone used, as for this work, a beam trawl. This month report forms a comparison and an addition to the fish species they had found, with emphasis on the determination of the diversity of this tropical fish fauna and a comparison with temperate regions.