Coldwater fish such as Goldfish and Koi do not require a diet that is high in protein. However, they will do better with a diet that is high in carbohydrates. Nutrafin basix Goldfish Food provides a complete diet – fortified with multi-vitamins and stabilized vitamin C – for all coldwater fish. As a general rule, aquarium fish should be fed a varied diet containing freeze-dried foods such as Nutrafin basix Blood Worms. Bottom-feeding species should be fed Nutrafin basix Staple Food Tablets. Available Sizes: Quart, 200 g (7 oz)