Stickwater is the nutrient-rich liquid pressed out of fish during the manufacture of fishmeal. After cooking and pressing, the solid presscake goes on to become fishmeal while the liquid — containing dissolved proteins, minerals, vitamins, and fine solids — is evaporated into a concentrate. Rather than being discarded, this concentrate is usually added back to the presscake before drying, which boosts the protein content and nutritional value of the finished fishmeal. Fishmeal is a major ingredient in aquaculture and animal feeds, so recovering stickwater improves both the economics and the sustainability of the process. The name comes from the sticky nature of the concentrated liquid.