Effects of Temperature on the Pharmacokinetics of norfloxecin (NFX) were studied in the cultured carp,Cyprinus carpio, and cel, Anguilla japonica, using high performance liquid chromatography (HPLC) originally developed for quinolone determination in livesrocks. Pharmacokinetics of NFX was apparently affected by ambiem water temperature. In a two-compaament model for carp after oral dosage of 20 mg/K01 at $13^{circ}C$ and $23^{circ}C$ and 5.20/hr, respectively. In carp the $K_{iota u}$, $T_{max}$and $C_{max}$ for carp at $13^{circ}C$ were 13.30/hr, 17.44 ${mu}g$/$mell$ and 7.00 ${mu}g$/$mell$, respectively. The" correspoeding values at $23^{circ}C$ were 3.93/hr, 15.40 ${mu}g$/$mell$ and 9.44 ${mu}g$/$mell$, respectively. The AUC and T were 355.66 ${mu}g$ hr/$mell$, and 12.70 hr at $13^{circ}C$ and 417,24 ${mu}g$ hr/$mell$ and 13.86 hrs at $23^{circ}C$, respectively. Similar trends were revealed in the NFX pharmacokinetics of eel kept under the two water temperature regimes aftee oral NFX dosage of 20 mg/kg. These pharmacokinetkal results have some implication in the optimal usage of recently introduced antibacterials in farmed fish, which were originally adapted for poultry and mammalian species.