Fish processing is the process of converting raw fish captured by fishermen into marketable fish and goods. Common by-products include fish heads, frames, skin, scales, and viscera, all of which have significant nutritional value. Others include bones, fins, and guts, which can be processed to produce PUFA-rich proteins. Discarding fish bycatch and fish processing byproducts is a frequent practice in both fishing businesses and fish processing companies. Given this reality, innovative green technologies are being researched and developed to extract added value components and high-value bioactive compounds from seafood and their byproducts. Food, pharmaceutical, cosmetics, agricultural, and energy industries are all expressing interest in and expanding their usage of fish byproducts. These industries are increasingly relying on the nutritional and functional qualities of fish by-products to improve product formulations and develop sustainable solutions. The growing global population and continued fight against poverty have created sustainability difficulties in a variety of fields, including agriculture. Agriculture necessitates the production of food and high-value substances, as well as the management of land, water, and crops, and the control of erosion and pests. Using fish by-products in agriculture can help achieve sustainable agriculture, promote public well-being, and maintain environmental balance.