The Paragua & ccedil;u River, located in the Atlantic Forest ecoregion in Bahia, Brazil, features streams with distinct characteristics and highly endemic fish fauna, particularly in the Upper Paragua & ccedil;u region. This study examined variations in the taxonomic and functional diversity of fish communities across three stream types (Type 1-cultivated areas; Type 2-rupestrian fields; and Type 3-forested areas) and evaluated differences between the dry and rainy seasons. Fourteen first- and second-order streams, covering the three described types, were sampled by electrofishing during both seasons. The results revealed no significant seasonal changes in the fish community structure. The functional diversity varied among stream types, being lower in rupestrian fields and higher in forested areas. Functional diversity was also influenced by local variables, notably with gravel substrates exerting a negative effect. Functional metrics such as functional specialization and evenness were positively influenced by forested areas but negatively impacted by cultivated areas. These findings underscore the role of environmental factors in shaping stream fish functional diversity and highlight the need for tailored conservation strategies in this semiarid region.