Fish soluble paste is a valuable by-product of the fish oil production process. During fish processing, a mixture of water and oil is obtained. After centrifugation to separate the oil, the remaining water-based fraction is condensed or dried to produce condensed fish solubles or dried fish solubles.

This semi-viscous, brown-colored liquid with a characteristic fishy aroma is rich in dissolved proteins, vitamins, and amino acids, making it highly beneficial for promoting growth.

Fish solubles have a high crude protein content, which may vary depending on the fishing season and the species processed. They are commonly used in aquafeed as a feed attractant, in organic fertilizers, and as an excellent source of water-soluble vitamins.