Aquaculture become the fastest-growing sector in the world. Out of 223.3 million metric tonnes of total fisheries and aquaculture production, seaweed contribution is about 36.5 million tonnes. Many varieties of seaweeds are now cultured worldwide with species including red seaweed (e.g., Gracilaria, Porphyra), brown seaweed (e.g., Laminaria, Ascophyllum), and green seaweed (e.g., Ulva, formerly Enteromorpha), these species are mainly utilized for the production of many bioactive compounds like Agar, Carrageenan, Alginic acid, polyphenols etc. these products are mainly used in biotechnology, media preparation, preparation of ice-creams and jellies etc. This article discusses the importance and use of seaweed-based bioactive compounds in aquaculture.