Rapid growing of human population has led to increasing demand of aquaculture production. Oreochromis niloticus or known as tilapia is one of the most globally cultured freshwater fish due to its great adaptation towards extreme environment. Besides, farming of tilapia not only involves small scales farming for local consumption but also larger scales for international market which contributes to a foreign currency earning. Extensive use of fishmeal as feed for fish and for other animals indirectly caused an increasing depletion of the natural resource and may consequently cause economic and environmental unstable. Microalgae biomass seems to be a promising feedstock in aquaculture industry. It can be used for many purposes such as live food for fish larvae and dried microalgae to substitute protein material in fish feed. The microalgae replacement in fish feed formulation as protein alternative seem potentially beneficial for long term aqua-business sustainability. The present chapter discussed the potential of microalgae as an alternative nutrition in fish feed formulations, specifically Tilapia.

This study was conducted to determine the potential of Scenedesmus sp. from phycoremediation as fishmeal replacer in formulated fish feed targeted for Oreochromis niloticus. Formulated fish feeds were designated with Formulation 1 being the control; in Formulation 2 and 3, 2 % of fishmeal was substituted with Scenedesmus sp. cultivated in Bold’s Basal Medium, and in artificial wastewater, respectively. It was found that supplementation with Scenedesmus sp. did not alter the hardness of the feed pellets (p>0.5), but the water stability of Formulation 2 and 3 was significantly lower than Formulation 1 (p<0.05). Zero correlation was established based on the fishmeal content with water stability (p>0.05). Negative correlation was determined between moisture content and water stability of Formulation 2 and 3 (p<0.05). This study showed the phycoremediation ability of Scenedesmus sp. in artificial wastewater with removal efficiency of 12.42 % and 49.25 % for Zn and Fe, respectively. It also found that biomass productivity of microalgae was lower in artificial wastewater compared to that in Bold’s Basal Medium. Overall, the results of the study suggested the sustainability of wastewater-treated microalgae as fishmeal replacer had little effect on physicochemical properties of fish feed.