Taste panel assessments of taste, texture, and grade, and estimations of soluble actomyosin and of fat spoilage on plaice fillets after frozen storage at + 10°F. (−12 °C.) are reported. The plaice became unpalatable at 6 to 7 months as compared with 2 to 3 months for cod and about 8 months for Atlantic halibut at +10°F. Ascorbic acid was not effective in preventing lipid deterioration. A relationship between protein denaturation and the lipid content of the fish and its deterioration is suggested.