Remember, any leftover food will become rotten and pollute the water, which cause disease (velvet).

You may notice some fries are gathering at the leaf on the bottom. This is because when the leaf decomposed, it will produce Infusoria. A source a tiny food for fries. However, this food will feed the fries for first 1-2 days.

Strong Betta fries can straight away eat Microworm or Daphnia. The weak one will eat Infusoria until they are strong enough for Microworm or Daphnia. Put some tubifex worm or snail in the spawning tank, so that its will eat the leftover food to avoid water pollution.

Syphon the leftover 2 week after fries are free swimming. Thereafter, do a 50% water change, raise additional 2 inches of water and add some salt weekly. If not, the ammonia built up will kill the fries.

If you take care of the fries properly, they should be able to eat tubifex after 2 weeks old. The main food now can become tufibex. The reason is tubifex wouldn't die easily in the water and fries grow faster and stronger eating tubifex worm.

At 4th weeks, they should be around 1 to 1.5cm. You can transfer them to bigger tank and they will grow tremendously fast.