Tryptone yeast extract salts (TYES) agar is a culture medium that can be used as the primary isolation medium for Flavobacterium columnare and F. psychrophilum. Growth of Flavobacterium spp. requires a culture media with a lower nutrient content than that used in general-purpose mediums such as brain heart infusion agar andtryptone soya agar. The tryptone and yeast extract provide the required carbon, nitrogen and vitamins. Calcium chloride and magnesium sulphate provide the required minerals. Agar is a solidifying agent.