Aquaculture systems produce large amounts of aquatic animal excretion and nutrients which contribute to water pollution. There are presently many chemical, biological or physical processes to treat waste water. One of the bio-remediation processes conducted in Thailand uses Caulerpa. The waste water is treated in a drainage ditch where Caulerpa grows, which naturally absorbs the nutrients. Water quality is improved before its release into the environment. This is a low cost method for water improvement in aquaculture business.