Breeding Siamese Fighting Fish
The Siamese Fighting Fish, or Betta splendens, are bubble-nesters that breed by collecting and tending to their eggs in bubbles at the aquarium’s water surface.
The Betta splendens or the Siamese Fighting Fish tropical freshwater aquarium fishes that are known and bred for their exotically colorful finnage. As “labyrinth” fishes, also known as Anabantids, they have the capability to breathe air and survive in what would normally be considered unpleasant habitats such as filter-less, non-aerated tanks, or even individual jars. This preferred solo existence, however, is actually for their own health and safety because in a community, Betta males will seek each other and fight to death.
Most labyrinth fishes, the Betta included, are bubble-nesters. To successfully breed the Betta, you need an average-sized aquarium that is very lightly aerated and heavily planted with vegetation reaching up to the surface. Floating plants with trailing roots will also serve the purpose because the fish will build their bubble-nests among the plants close to the water surface. The plants will hold the bubble-nest in place.
Use a tight-fitting cover for the tank so that humidity remains high at the surface. The humidity will prevent the bubble-nest and eggs from drying up.
At breeding time, the male Betta chooses a small area among the plants at the water surface to build a nest. He gulps air through his mouth and expels them in the water through his gills. The expelled bubbles are covered with sticky mucus; they float upwards (but don’t pop), and remain held together, afloat, by the plant leaves.
The male then courts a female and lures her under the bubble nest. When the female is ready, the pair engages in a tumbling embrace where eggs and milt are released into the water. Betta eggs are heavy so they sink to the bottom. As soon as the male recovers from the embrace, he goes about catching the eggs with his mouth and depositing them into the bubble nest. The female joins the male in collecting the eggs, after which, they resume spawning. The tumbling, spawning, and egg-catching activity lasts for several hours, giving rise to a nest of about 200 to 300 eggs.
After spawning, the male assumes its paternal role: to watch over the nest and pick a fight with whoever comes near, including the female. At this point, the female should be removed from the breeding tank.
The male will continue to reinforce the bubble nest, diligently returning eggs that fall off or float away back into the cluster. In two to four days, the fry will emerge. The male must be removed at this point, because he will tend to consider the small fishes as food. The fry should then be fed with infusoria or any appropriate fine-powdered fry food.