Improving Fish Production in a Locally-Designed Aquaculture System

This study presents a lab-scale recirculation aquaculture system (RAS) designed to reduce, recycle and reuse fish farm wastewater. The system has a trickling filter as a biological treatment unit, a settling tank and a fish tank. The tank housed four samples of fish for 21 days. Then, there was a continuous recirculation of highly concentrated fish farm wastewater for 16 days, to build a considerable mass of bacteria on the filter. The reason is to ensure adequate nitrification processes, after which fish were put into the fish tank for rearing. The result of water analysis showed that the ammonia, nitrite, nitrate, dissolved oxygen, pH and total suspended solids in RAS were within the acceptable level for African catfish culture. The RAS for the 21 days culture used up 32.89L of water to produce a percentage increase in weight gain ranging from 17.69% - 37.05%. That showed that the system is efficient for maintaining the required effluent quality for catfish rearing.