Originally Posted by registereduser
A better question would be Why would anyone want to give a betta peppermint?
Exactly. I'm not sure why one would want to do that.
I can't seem to find the page I was looking on that said why - I wasn't even looking at info about bettas, I was researching worm composting bins when I came across it. It was talking about how peppermint can be used as a pest repellent and you shouldn't put it in with your earthworms. It also listed other animals you shouldn't give it to, aquarium fish were among the many listed there.