check the PH in the water,
it looks like they have a big bubble in their side
Betta are social fish. There is nothing wrong.
It probly is a female
Female Betta fish do not make bubble nests.
http://www.firsttankguide.net/betta.php
The male will make a bubble nest when the female is about to lay her eggs.
they can. but it is VERY rare. usually you would see a bubble nest.
Place a female in close proximity where he can see her.
It's not something on the fish. He will blow a nest of bubbles on the surface of the water that hold up the eggs.
Betta fish reproduce through a process called spawning. The male builds a bubble nest at the water's surface, then courtship and mating take place. The female releases eggs, which the male fertilizes, and he collects them in the bubble nest to protect them until they hatch.
it depends on if they have egg's in there but if not they don't get angry.
Male Betta fish make bubble nests when they are happy ^^ I have only had male Betta fish and after a day or two of playing with them and feeding them or even just talking to them they make their nests to show you that you made them happy.