A rearing fodder of extruded fodder type, comprising proteins, fats and carbohydrates, for freshwater fish, wherein the fish is larger than 2 grams, and wherein the freshwater has a content of CO2 being above 5 milligrams/liter, wherein the fodder has an increased content of at least one of the minerals: phosphate (P), potassium (K), calcium (Ca), sodium (Na) and magnesium (Mg) beyond what exists naturally in the used protein raw materials, fat raw materials and carbohydrate raw materials, wherein the collective amount of minerals in the extruded fodder is at least 10%, on a dry substance basis, of the total weight of the fodder, and wherein one or more of the minerals phosphate (P), potassium (K), calcium (Ca), sodium (Na) and magnesium (Mg) is/are added beyond what exist in the used protein raw materials, fat raw materials and carbohydrate raw materials.