In this study, a newly synthesized thiazolidinedione derivative, TD49 with a highly selective algicide to red tide, was examined in order to evaluate the bioconcentration on aquatic organisms of coast. BAF (accumulation of TD49 by aquatic food chain) and BCF (accumulation of TD49 by sea water) were examined employing the shrimp (Fenneropenaeus chinensis) as the feed organism, and the olive flounder Paralichthys olivaceus as a consumer in marine ecosystem. Bioconcentration degree in sea water showed that the order in P. olivaceus was viscera > gill > muscle. The average BCF values of TD49 were 67.70, 63.32 and 20.25 at viscera, gill and muscle, respectively. Bioaccumulation degree using feed showed that the order in the organs of P. olivaceus was viscera > gill > muscle. The average BAF values of TD49 were 175.89, 114.88 and 32.59 at viscera, gill and muscle,