To provide a solid feed for fish culturing excellent in storage stability suitable for culturing conchostracan, etc., such as Peneus japonicus, etc., having ascorbic acid activity by adding L-ascorbic acid 2-phosphate to feed for fish culturing, heating and pelletizing.

This solid feed for fish culturing is obtained from feed for fish culturing such as fish flour by adding L-ascorbic acid 2-phosphate salt such as magnesium L-ascorbic acid 2-phosphate preferably in amount of more than 0.003m mole (per 1Kg feed) then heating this mixture and pelletizing.