Tiger Barbs are typical egg scatterers. They scatter a large number of eggs, 2-300, and will then spend the rest of the day looking for them and eating them.
If you want to breed them, (or the vast majority of other Cyprinids), you should set up a well planted breeding tank. Keep the males and females apart and condition them with high quality food. After a couple of weeks conditioning, take a good male and a fat female and place them in the breeding tank at night, with the lights out. They usually begin to spawn when it gets light, (cover the tank if that is too early), as soon as they stop spawning and start searching for eggs, take them out.
If the fish do not start to spawn, try doing a 10% water change with water that is a couple of degrees cooler than the tank, which you should have at about 26C.
For the eggs to hatch, the water needs to be slightly acidic ~ 6.5pH and VERY soft.
