Water pollution is a severe problem for human beings. Sewage and hot water\rcoming from homes and factories have changed the environment for aquatic\ranimals. To manage a polluted environment, an accurately designed monitoring\rsystem is needed that will detect signs of toxic material or increase in temperature as\rfast as possible. A new and more accurate bio-monitoring system, which involves\ractual creatures, needs to be developed to save the aquatic environment from\rpollution.\rThis experiment focused on discovering a new way to monitor aquatic\rcreatures by observing the behavioral patterns of the medaka and observing how\rthey changed when exposed to external stress, especially an increase in temperature\ror exposure to insecticide. The behavioral patterns of the medaka were observed and\rmeasured by a tracking program called the Movement Viewer. In the transition\rperiod, that is, when the temperature was raised from 25°C to 35°C, the total moving\rdistance of the medaka suddenly increased compared to that in 25°C. When the\rmedaka was in a temperature of 35°C, it slowly adapted to the new environment and\rthe total moving distance showed a similar value to that in 25°C. For section\rdominance, the medaka showed a sudden increase in the dominance of the top part\rof the tank, meaning that the medaka tended to swim on the surface of the\rexperimental aquarium. Again, it slowly adapted when the temperature had\rcompletely changed to 35°C.