Feedstuff for animal plankton

A feedstuff for animal plankton, comprising microorganisms containing n-6 docosapentaenoic acid and docosahexaenoic acid as well as a cell wall crushing product of microorganisms containing eicosapentaenoic acid. One characteristic of this feedstuff is that eicosapentaenoic acid, n-6 docosapentaenoic acid and docosahexaenoic acid are contained with good balance in the lipid component of this feedstuff. This feedstuff realizes production of fingerlings (larval young fish, etc.) being resistant to low temperature stress and handling stress having posed a problem in the production of fingerlings such as larval young fish.