Cannabidiol on aggression in betta fish ( Betta splendens )

Cannabidiol (CBD) was first isolated in the 1940s and its drug structure was established in the 1960s. It has risen significantly in popularity since then and has been observed to reduce inflammation and anxiety in patients. CBD is easy to obtain and consume, therefore, its common use is rising and has spread to use in pets and children. Few studies have focused on the use of CBD as a solution to aggression. In our study, we tested if CBD is effective in reducing aggression in Siamese fighting fish ( Betta splendens ) induced by territorial interactions. Betta fish were exposed to controls (water or acetone) and CBD treatments ranging from low, medium, and high (2, 10, and 20 mg CBD/L, respectively), and their behaviors after the visual introduction of an intruder fish were recorded. CBD reduced the odds of aggressive behavior in treated fish. Seventy-five percent of all control fish exhibited aggressive behaviors, while only 17% of CBD-treated fish displayed aggression. Especially, the low CBD dose seemed effective at preventing aggressive behaviors but fish also appeared more lethargic than in any of the other treatments. However, when CBD-treated fish displayed aggressive behaviors, CBD did not appear to reduce the amount of time fish spent being aggressive compared to aggressive fish that did not receive any CBD treatment. While the long-term effects of CBD still have to be examined, our study indicates that CBD might be effective in reducing aggression in Betta fish and potentially other pets.