The fishery industries have continuously increased over the last decade. This growth comes accompanied by a high volume of by-products released to environment, because these industries discard between 60 and 70% of their production as waste. This waste includes fish whole or part from these such as fillet remains (15–20%), skin and fins (1–3%), bones (9–15%), heads (9–12%), viscera (12–18%) and scales (5%). This by-products are rich in proteins and lipids which of several nature, which can be recovered to obtain compounds of high added value. In this chapter, some methods to recover compounds from fish by-products will be discussed. Among others, will be discussed topics about postharvest of fish, by-product releasing, enzymatic hydrolysis of by-product and bioactive peptide obtaining from fish waste.