Article in English: Purchase pellets that are made from fishmeal or shrimp meal. Occasionally supplement with a piece of blanched pea once per week or fruit flies with wings attached. A betta’s stomach is about the size of its eyeball, so feed it about that amount twice per day. That translates to approximately 2 or 3 pellets per feeding.  Let pellets soak in water 10 minutes before feeding. This will prevent them from swelling up inside your fish’s stomach.  If your fish has a rounded belly, you may be feeding it too much. If its belly looks a little caved in, then you might not be feeding it enough. Uneaten food becomes toxic in the water, contributing to the growth of bacteria and ammonia levels. Bacteria in the tank will in turn start attacking your fish. If your fish seems to have trouble digesting food or seems constipated, you can give it a rest by not feeding it once a week. This will not harm the fish and will allow the fish to work through some of the food already in its system.

Summary in Vietnamese:
Cho cá chọi xiêm ăn thức ăn phù hợp. Không cho cá ăn quá nhiều. Dọn sạch thức ăn thừa trong bể. Cho cá nhịn ăn mỗi tuần một lần.