CERTAIN AMINO ACIDS ARE POTENT FISH-FUNGICIDES

The potential fungicidal abilities of L-cysteine, L-valine, L-phenylalanine, L-methionine, L-alanine and L-isoleucine have been tested in vitro on five fish pathogenic watermoulds, four of Saprolegniaceae, viz., Achlya orion Coker & Couch, Aphanomyces laevis deBary, Dictyuchus sterile Coker, Saprolegnia diclina Humphrey; and one Blastocladiaceae, viz., Allomyces arbuscula Butler. The lowest concentration having fungicidal ability has been found to be 0.25%. Tolerance tests have also been conducted using Colisa lalius Hamilton and Channa punctata Bloch as test fishes and 0.25% has been recommended as Fungicidal Non-Toxic Concentration (FNTC) for the applicability of these amino acids as fish-fungicides.