The newest diet: Blackwater Gold-N Professional. We feed our broodstock and our best ponds gold diet. It's formulated to be highly digestible as well as grow the fish quickly. One of the main ingredients that makes it stand out is the Bascillus Subtillus -a live digestive enzyme that helps break down nutrients in the fishes' digestive tract. You will see this concept being advertised in yogurts at a premium. Bacillus Subtillus remains one of the most potent and beneficial of all health-promoting and immune-stimulating bacteria.