The study on water quality and hispathology of climbing perch (Anabas testudineus Bloch) was conducted to analyze water condition, water quality determine the pollution index, and to analyze the liver tissue of the fish in the area of diamond and gold mining areas. Samples were taken from three observation site. The analysis of water quality and fish’s liver tissue were conducted in laboratory. Histology observation using the microtechnique method was conducted by preparing histological preparat of climbing perch. Based on classification of water quality, the parameter of alkalinity, mercury (Hg) in liver, Total Suspended Solid(TSS), Hg in worms, the depth level of site, ammonia (NH3), Hg in snails, Dissolved Oxygen (DO), and pH were classified into Class B. The pollution index was between 1.0 < IP ≤ 5.0. Therefore, the area of Cempaka diamond and gold mining was mildly polluted. Tissue damage was around 50-80 %. There were severe level types such as inflammation, cloudy swelling, focal necrosis, karyolitic, hemorrhage, and hepatoma. Keywords: Mercury pollution, Hispathology, Climbing perch