Fishbone (FB) is a nutritionally dense by-product of fisheries processing, which is a good source of Ca and other elements. This study aimed to determine the effect of sonication and water bath treatments on the size and nutritional value of Pangasius bone powder. Pulverized FB was soaked in 40% lime solution (pH 2) under different conditions in a sonicator and water bath for 30 min. and 60 min. at 60 C, and then powdered. The whiteness index (WI), pH, particle and distribution size, proximate and mineral contents of FB powder were investigated. This study showed that sonication treatments were 89.09-89.17 for WI, 6.99-7.14 for pH, 860.15-1029.3 nm for particle size, 3.66-3.95 % for fat, 14.62-16.10 % for protein, 50.48-50.91% for Ca, 14.77-15.08 % for P and water bath treatments were 88.91-88.93 for WI, 7.36-7.43 for pH, 734.5-959 nm for particle size, 3.22-3325 % for fat, 14.78-15.23 % for protein, 50.97-50.95 % for Ca, and 14.97-14.99 % for P. Both showed a mono-modal size distribution and trace amounts of other minerals in all treatments. In conclusion, a 60-minute water bath treatment is a promising method for reducing the particle size of FB powder without significantly altering its nutritional composition.