Reporting sightings of sea water change brown at bangsan. Caused by plankton groups Chaetoceros spp.,which reported that non-toxic. (Charitkaun et al ., 2008). There are also reports that Chaetoceros calcitrans, C. gracilis and Skeletonema sp. would have an extremely important role in the rearing of tiger shrimp. (Phetmani et al., 2000 ; Limsuwan and Chanratchakool,2004).