The experiment in triplicate group of prawn (30 prawn per group) with an initial weight of 2.5-2.6 g, were fed until apparent satiation with 32% crude protein diet containing various Chlorella levels ranging from 0 to 10% (Diet I, Diet II, Diet III, and Diet IV) for 56 days. At the end of the feeding trial, prawn given Diet IV gave the optimum growth and percentage survival which also contributed to the best feed efficiency. There was no significant difference in FCR in all treatments (p