The Tripa Peat Swamp Forest (TPSF) suffers from deforestation due to agriculture, this habitat degradation potentially has a negative impact on fish biodiversity and community assemblages. The objective of this study was to develop an inventory of the fish fauna, evaluate the spatial variation in assemblage structure, document alien species, and quantify the economic value of fish species found from the area. Fish assemblages from the main rivers and tributaries of TPSF were sampled on May to June 2013. A total of 764 individuals were sampled during the survey, constituting 34 families, 47 genera, and 73 species where 46 species are categorized as fish consumption, 17 have potential for aquaculture, and 10 species have potential for ornamental, and three are non native. Cyprinidae is the predominant fish family within the TPSF. Fish assemblages were generally characterized by small population size for each species and low similarity among sites, reflecting the distinctive nature of each sampling site.