The anaesthetic potency of benzocaine-hydrochloride in three freshwater fish species

Abstract

Anaesthesia was induced in the common carp, Cyprinus carpio, tiiapia, Oreochromis mossambicus and rainbow trout, Salmo gairdneri, at concentrations of 25; 50; 75 and 100 mg/1 of benzocaine-hydrochloride as well as neutralized benzocaine-hydrochloride at water temperatures of 15; 20 and 25 °C. The results obtained indicated intra-and interspecific differences in the susceptibility of fish to anaesthesia due to metabolic, chemoreceptive and temperature tolerance differences in and amongst the three species.