JBL ProNovo Red Holiday is a holiday food for goldfish and veiltails. Most aquarium fish, excluding juveniles, would even go without food for a day or two - just like in the wild. But then many aquarium owners get a guilty conscience and that's why JBL ProNovo Red Holiday is also available for a short absence. The food blocks in JBL ProNovo Red Holiday are made of a natural calcium compound which slowly dissolves when the fish nibble on it. The calcium is even positive for many aquariums as it adds some calcium to the water (general hardness/GH).JBL ProNovo Red Holiday+ provide your goldfish and goldfish breeds with a food store for up to (3x) 6 days+ use: add food block to the aquarium. It sinks to the bottom and (1 block) provides food for about 1-3 fish of 8-20 cm size for 4-6 days+ the block consists of a calcium compound that adds some general hardness to the water when dissolved. It dissolves slowly as the fish intake the food+ natural raw ingredients without artificial additives