ABSTRACT DICUANGCO, JOHN DAVE A. May 2023. BIOCHEMICAL AND PHYSICAL CHARACTERIZATION OF BAMBOO CULM ACTIVATED CHARCOAL AS WATER CONDITIONER AND ITs HISTOPATHOLOGICAL EFFECTS ON Pampanga State TILAPIA, Master of Science in Biology, Agricul tural University, Maga lang, Pampanga Adviser: Dr. Rafael R. Rafael Activated charcoa l is an adsorbent material known for its high surface area and used for various applications, including aquaculture. However, its effects on physical and biochemical water parameters and fish health are not fully considered. In preparation for bamboo activated charcoal (BAC), bamboo culm of Dendrocalamus giganteus was carbonized and activated using chemi cal activation of ZnC12 under specific ten o. niloti cus with three replicates were established: BAC-treated (T1), commercial AC (T2) , and negative control (T3) and observed for 24 hrs wit.h three hours intervals. Res11lts showed a significant increase of EC and TDS after application and a signifi cant decline of NH, and PO43- from an 18-hr to 24-hr period between T1 and T3. Gross examination shOwed no lesions in selected organs of 0. niloticus, but histopathological examination suggested the presence of cell injuries and damages in all treatments. However, significant differences in the intensity of gills and liver between T1 and T3 were observed. The produced BAC had a high net profit and cost- bene fit ratio. Hence, BAC can be suggested as a low-Cost water temperatures. Three treatments containing Conditioner in treating NH3 and PO43- but it may damage gills and liver at tissue level of 0. niloticus. Keywords: liver, histopathology, tilapia activated charcoal, ammonia, phosphate, gills.