For breeding, the female is displayed to the male (but separated in a clear container or separate tank) to see if he's interested. He will build a bubble nest & display to her. When timing is right, the female us introduced under strict supervision. The male wraps his body around the female to encourage her to release eggs which he fertilizes. He will then pick up the eggs in his mouth & deposit them into the bubble nest. The female is then removed fir her safety, & the male guards/maintains the eggs/nest until hatching.
Honestly, breeding bettas is a HUGE undertaking - they have many babies which then need to be fed tiny foods & will need to be separated & males kept separately.
Honestly, breeding bettas is a HUGE undertaking - they have many babies which then need to be fed tiny foods & will need to be separated & males kept separately.