"Most Cyprinids, which includes Barbs, Danios, Rasbora, and Black-tailed sharks, are free spawning. This means they will discharge the eggs and sperm into the open water.
Usually an increase in temperature and feeding plenty of live foods will trigger spawning. The eggs will then adhere to whatever they come in contact with: leaves, decorations, gravel, etc. The eggs hatch quickly, usually within 30 hours at which time the fry can eat finely powdered flake food followed by baby brine shrimp after a week or so.
The parents will eat the eggs and the fry so some means of protecting the eggs is needed. To accomplish this you can use spawning grass, marbles in the bottom of the aquarium, or a grating that the eggs can fall through but the parents cannot. After spawning it is a good idea to remove the parents.
One of the notable exceptions to this method of breeding is the practice of the Bitterling, Rhodeus sericeus amarus, who protects the eggs within the Mussel and defends them after they have hatched."
from
http
/animal-world.com/encyclo/fresh/info..._fish.htm#barbs
