How much fish does a blue whale eat?

Blue whales don't eat fish; their diet is almost exclusively krill. Krill are tiny crustaceans. They also eat another related crustacean called copepods. Blue whales can hold 90 kilograms (200 pounds) of mixed food and water in their mouths. They can eat up to 3600 kilograms (8000 pounds) of food in a day.