Betta eggs take 36 to 48 hours to hatch after spawning. The male and female swim close together, and the female releases her eggs, which the male fertilizes. The male scoops up the eggs and spits them into the bubblenest.
Before spawning takes place, the male betta blows a bubblenest for the eggs. When the pair are ready for spawning, they display intense coloration, and the female has a protruding breeding tube behind her pelvic fin. Once the eggs are in the bubblenest, the male becomes aggressive toward the female, so she needs to be removed. The male tends to the nest until the fry hatch.