While bloodworms are about as high in protein as blackworms you are paying for a lot of water with the frozen. As far as I'm concerned there is no advantage to feeding frozen so why pay for the water. 10 blackworms cubes is a LOT of blackworms. I feed no more than 2 or 3 cubes at a time and 1/2 cube in some of my say 1" to 2" tanks. A tank with 10 to 12 4" discus will get no more than 3. Feeding more food at one time will not bulk up your fish. They can only eat so much.