Abstract: A composition for controlling or preventing microsporidia in a fish or a seafood is prepared by using, as an active ingredient, at least one compound selected from the group consisting of compounds represented by the following chemical formula (I): (wherein, R2, R4, R5, R6 and R7 each independently represent a specific substituent), pharmaceutically acceptable salts thereof, and compounds generating the compounds represented by the chemical formula (I) by metabolism in the body of the fish or the seafood. By using this composition for controlling or preventing microsporidia in a fish to or a seafood, a method for controlling or preventing microsporidia in a fish or a seafood is provided, which prevents microsporidian infection in the muscle or organs of the fish or the seafood, and/or suppresses the growth of microsporidia in the muscle or organs of the fish or the seafood, and/or highly effective in eliminating microsporidia from the body of the fish or the seafood and also excellent in safety.

Abstract: A composition for controlling or preventing microsporidia in a fish or a seafood is prepared by using, as an active ingredient, at least one compound selected from the group consisting of compounds represented by the following chemical formula (I): (wherein, R2, R4, R5, R6 and R7 each independently represent a specific substituent), pharmaceutically acceptable salts thereof, and compounds generating the compounds represented by the chemical formula (I) by metabolism in the body of the fish or the seafood. By using this composition for controlling or preventing microsporidia in a fish to or a seafood, a method for controlling or preventing microsporidia in a fish or a seafood is provided, which prevents microsporidian infection in the muscle or organs of the fish or the seafood, and/or suppresses the growth of microsporidia in the muscle or organs of the fish or the seafood, and/or highly effective in eliminating microsporidia from the body of the fish or the seafood and also excellent in safety.