Red water worm is very valuable betta food. Betta will growing faster and has a perfect form quickly. It is available for at least 1 month old betta fish.
You can keep red water worm for your betta about a month. They still alive if the water is good enough. But the major problem of water worm is about the dirty. This type of fresh food is the top of impurities. Before give it to your betta fish you need to wash it well.
If you don't wash it good enough , the disease will come.... such as stomach parasites.