The pharmacokinetics of norfloxacin-glycine acetate (NFXGA), a newly formulated norfloxacin, was investigated in healthy flounders at two different seawater temperature (at 12°C and 20°C) varying concentrations (100 ppm and 10 ppm), using dipping administration. It was shown that the elimination half-life (T_1/2) of norfloxacin at 20°C (10 ppm: 13.95±1.18 hr, 100 ppm: 11.71±1.32hr) was significantly shorter than that at 12°C (10 ppm: 16.61±1.47 hr, 100 ppm: 16.32±1.19 hr) in flounders. Mean residence time (MRT) was calculated at 12°C (10 ppm: 194.87±29.88 hr, 100 ppm: 1, 222.37±161.45 hr) and 20°C (10 ppm: 168.42±25.85, 100 ppm: 606.14±122.75 hr). Meanwhile, in the flounder tissue distribution of norfloxacin. It was shown that serum, muscle, kidney, and liver exhibited different elimination half-lives of norfloxacin.