All pond fish, including goldfish and koi, will enjoy these Petbarn Sinking Spirulina Algae Wafers. The fact that they sink means that they are perfect for bottom feeders and as all fish need a source of algae in their diet, you can be sure that your fish will be kept happy and healthy whilst fed on these wafers. They are rich in vitamins, minerals and antioxidants and contain 35% protein.