Temperature-dependent pharmacokinetics of ciprofloxacin (CIP) was studied in the cultured olive flounders, Paralichthys olivaceus, and black rockfish, Sebastes schlegeli using high performance liquid chromatography (HPLC) originally developed for quinolone determination from livestock. Pharmacokinetics of CIP was apparently affected by ambient water temperature. In a two-compartment model for flounders after oral dosage of 20 mg/kg, $K_{01},;at;13^{circ}C$ and $23^{circ}C$ were 4.18 and 1.20/hr, respectively. The $K_{10},;T_{max};and;C_{max};at;13^{circ}C$ were 5.574/hr, l4.37${mu}g/mL;and;3.15{mu}g/mL,$ respectively. The corresponding values at $23^{circ}C$ were l2.84/hr, 15.39${mu}g/mL;and;6.38{mu}g/mL$, respectively. The AUC, $T_{1/2} (alpha);and;T_{1/2};(eta)$ were 278.23 ${mu}g cdot hr/mL$, 0.24hr and 47.02hr at $13^{circ}C$ and 3l7.8l${mu}g cdot hr/mL$, 0.30 hrs and 60.78hrs at $23^{circ}C$ for the flounder, respectively. Similar CIP pharmacokinetics were revealed in the black rockfish after oral dosage of 20 mg/kg under the two water temperature regimes. These pharmacokinetical results have some implication in the optimal usage of recently introduced antibacterials in the farmed fish, which were primarily adapted for poultry and mammalian species.