PROBLEM TO BE SOLVED: To provide fish feed with a low fish content, a fish disease control agent, and a fish disease control method which can breed a fish with fish disease resistance, and suit fish's taste.SOLUTION: Fish feed contains (A) less than 50 mass% of fish-origin protein materials, (B) substitution of fish protein material, and (C) a supernatant liquid obtained by acid deposition of a neutral to alkaline water extract from glycyrrhiza.