I have no idea Roan, except that maybe, being an aggressive fish, they have to find something to take it all out on...lol.....my bettas EAT the dang wafers !! I've dropped one in at night for my otos and in the morning I find the bettas belly swollen and greenish...lol....not sure if the oto got any or not, they don't seem to really like them anyway, but will eat them if the algae in the tank is a bit sparse...and if they can keep the dang betta away from them !