How Much Potassium Does Fish Have In It?

How Much Potassium Does Fish Have In It? Seafood. Popular fish like salmon, mackerel, halibut, tuna and snapper all have more than 400 milligrams of potassium in a 3-ounce filet. Is fish high in potassium? Seafood. Popular fish like salmon, mackerel, halibut, tuna and snapper all have more than 400 milligrams of potassium in a