PROBLEM TO BE SOLVED: To prevent cultivated fish, especially large-sized cultivated fish, from effecting death suddenly and/or in great quantities in its young state.SOLUTION: A cultivated fish death inhibitor is provided, comprising γ-oryzanol as an active ingredient.【課題】養殖魚、特に大型養殖魚の養殖に関し、幼魚、稚魚の時点における突発的な死、及び/又は大量に死に至るのを防ぐ。【解決手段】γ-オリザノールを有効成分として含んでなる、養殖魚死亡抑制剤。【選択図】図1