You need to feed bbs more often, especially at the beginning. They provide important enzymes which will help kick-start the digestive enzymes in the gut of the fish. Rotifers will do that too but they are too small for banggais. After 2-3 days of feeding bbs you will have to enrich the bbs with fatty acids like DHA, which is why I passed you the Selco. If you skip this step, fishes easily go into shock and they just die.