Effect of Water Temperature, Fish Age, and MS-222 Concentration on the Anesthetization of River Pufferfish, Takifugu obscurus

Abstract

The river pufferfish (Takifugu obscurus) is a valuable species in aquaculture and genetic studies. Usage of fish anesthetics aids in the easier handling of fish during aquaculture. However, there are no studies on appropriate conditions required for effective anesthetization of pufferfish. This study aims to determine the optimal conditions (fish age, water temperature, anesthetic concentration) needed for the most common fish anesthesia, MS-222, to anesthetize T. obscurus. We tested three different water temperatures (20°C, 24°C, and 28°C), three different anesthetic concentrations (125 mg/L, 150 mg/L, and 175 mg/L), and two different fish ages (one- and two-year-old). Appropriate anesthetization conditions for T. obscurus ranged from 150 mg/L to 175 mg/L of MS-222 at 24°C to 28°C for one-year-old fish. For two-year-old fish, the appropriate conditions ranged from 150 mg/L to 175 mg/L of MS-222 at 28°C. However, to minimize side effects and risks, 150 mg/L of MS-222 at 24°C for one-year-old fish and 175 mg/L of MS-222 at 28°C for two-year-old fish are recommended for effective anesthetization.