The Chlorella sp. growth in different treatments depicted similar growth patterns with relatively short lag phase followed by an exponential phase in the first five days. It was observed that the death phase began on Day 10 towards the end of the treatment period. As shown in Fig. 3, the microalgae exhibited a short lag phase of one to two days when the cell concentration was increased at about two-folds of the initial biomass density. The short lag phase showed that the microalgae had excellent adaption characteristics to the aquaculture wastewater. Rolfe et al. (2012) reported that microalgae population synthesized new metabolites and performed homeostatic regulation as it was transferred to new environment and thus exhibiting the lag growth phase.