Streams within urban forest or surrounded by developments may support important freshwater biodiversity. This study assessed freshwater fish diversity, assemblage structure, and environmental relationships in three streams located within a reforested landscape and recreational forest in Selangor, Malaysia. Fish sampling was conducted monthly from June 2022 to July 2023 using backpack electrofishing along standardized transects. A total of 19 species representing 11 families were recorded, with Cyprinidae being the dominant family. Species composition differed among streams, with one stream supporting several unique taxa and a distinct assemblage structure. Diversity analysis indicated the highest diversity in the conservation-buffered stream (C-BS) (H′=1.582), while the recreationally impacted stream exhibited lower evenness and greater dominance by opportunistic species. Abundance–biomass comparison analysis revealed differences in community stability among streams, indicating varying levels of ecological disturbance. Water-quality measurements showed significant variation only in total dissolved solids among sites. Multivariate ordination suggested that environmental variables explained limited variation in assemblage structure, highlighting the role of habitat complexity and hydrological connectivity. These findings demonstrate that streams within urban forest can support diverse freshwater fish assemblages and contribute to biodiversity conservation within human-dominated landscapes.
