Following the technique used by Valle et al.5, who assayed
the toxic effect of various psychotropic drugs in
fish (Guaru = Phallocerus caudimaculatus Hensel, and
Lebistes = Lebistes reticulatus Peters), we determined
the mediun lethal dose (LD50) of strychnine sulfate in
a total of 1560 fishes of both species. In the test
group, ascorbic acid (0.5 mg/ml) was added to the individual
fish bowls, 12 hours before adding strychnine
sulfate in doses varying from 10 to 80