The use of duckweed chlorella combination as a protein supplement and the subsequent effects on tilapia fish fry would be a good way of reducing production costs in intensive tank tilapia culture. Thus an investigation was staged to identify the effects of duckweed and chlorella algae as feed supplements on Nile tilapia fry growth under the green water technique. Three experimental treatments were run in two replicates for an experimental period of 30 days where fry of the same initial weight and length average were fed on a 45%commercial feed. In T1 the tank had green chlorella water and 25% of the commercial feed replaced with duckweed, T2 had green chlorella water too but was fed on 100% commercial diet while as T3 had clear water with no algae and was also fed on 100% commercial feed. There was a significant difference in both the final weight and final length at the end of the experiment with treatment one indicating the fastest growth (p=0.002)and (p<0.05) respectively. The survival of the fish fry in T1and T2 was also significantly higher than that in T3 (p=0.001).Thus duckweed in green water can supplement the tilapia fry protein requirement while as chlorella algae improves survival of tilapia fry.

Keywords: Chlorella,Duckweed,Feed supplement,Nile tilapia