Eel is a highly migratory species, marine habitats andmigratory paths often cross the coastal waters of the national economy, butinvestigate the population structure and ecological traits of respect, is a bigchallenge fisheries science. Discharge flow studies exploring identitypopulation dynamics, distribution and behavior of fishing on fish stocks thebest weapon effects. This main objectiveof this study had two parts.The first part was comparingthe efficacy of 2-phenoxyethanol and cloveoil as anaesthetics in Japanese eel.The second part was using three diffident typeof tag and comparing the data.The fish exposed to 2- phenoxyethanol (400ppm、500ppm、600ppm)with respect to time to anaesthesia(mean 275 ,155 and 154 secondrespectively)and recovery (mean 186 ,368and3360 second respectively). In other hands, Cloveoil group (60ppm、80ppm) withrespect to time to anaesthesia (mean 684 and440 secondrespectively) and recovery (mean 684 and 440 secondrespectively). Two of deaths was observed in Clove oil group. Clove oil comparewith 2- phenoxyethanol may not be anappropriate anaesthetic for Japanese eel.The maximum depth of eel dive was 4 meters, and thenstayed at 1.3 meters to 2.7 meters. After that the tag might fell off and floated under the water surface.