http://www.firsttankguide.net/betta.php
it looks like they have a big bubble in their side
It probly is a female
because if the eggs were left unguarded, other fish would eat them. and it makes it easier for the dad to clean.
Female Betta fish do not make bubble nests.
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.
check the PH in the water,
the male betta does, the female just swims away.
Reviving a dead betta fish is not possible. Once a fish has died, it cannot be brought back to life. It is important to properly care for your betta fish to prevent it from becoming ill or dying.
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.