My Beta fish?

There has been strange behavior that started about a week ago. For some reason, my Bets fish both have phone bubbles at the top of their bowls. It almost looks like soap suds but it's not. They've never done this before and I'm just wondering if I should be worried. Also they won't keep still. They're Japping at everything. Banging their heads against the bowl every now and again. They've never done that before either. I only use store bought distilled sodium free water for their bowls and I feed them blood worms and flakes once every 3 days or so. So why have they started acting so weird? Is it mating season or something? How can you tell when a Beta fish is a girl or a boy? I have one solid red one and one solid blue one.