Is it healthy for betas to eat pleco food?

Keep in mind that many pleco foods have a fair amount of fish meal in them. (Which given most pleco aren't herbivores, but instead omnivores is a good thing.) Bettas will tend to eat anything. Plant matter isn't bad and in fact will help clean out their digestive system. I'd try and limit the betta's intake of the pleco food.

It would be b. distress