Presently, there is significant exploration of natural products as alternatives to chemical drugs, with the goal of mitigating adverse environmental impacts. This study investigates the wound-healing potential of Xylocarpus granatum bark extract in Siamese fighting fish, Betta splendens, a popular ornamental fish. The extract was prepared using the decoction method. Subsequently, the obtained extract was applied at concentrations of 60, 120, and 180 ppm to treat wounds in betta fish. These treatment groups were compared to a positive control group receiving 15 ppm oxytetracycline and a negative control group receiving no treatment over a 21-day period. The results revealed the fastest healing among groups treated with either 60 or 120 ppm of X. granatum bark extract. However, the 60 ppm concentration appeared more promising due to the highest survival rate (85.0±4.3%) among treated fish. Notably, neither the negative control nor positive control groups achieved complete wound healing within 21 days, and these groups had among the lowest survival rates. Regarding the healing effects on various tissue layers, muscle tissue healing was slower in the 60 ppm group compared to the 120 and 180 ppm groups. However, for connective tissue, dermis, epidermis and scale tissues, the 60 ppm treatment group demonstrated the fastest wound healing rates. Based on these findings, X. granatum bark extract shows potential as an effective wound healing agent for B. splendens, particularly at a concentration of 60 ppm. This natural product could offer benefits for the aquaculture industry and ornamental fish enthusiasts while mitigating environmental impacts.