Abstract: For the purpose of elucidating the rapid growth of the Silver Carp (Hypophthalmichthys molitrix) in nursery ponds blooming with the blue-green alga,Ana-baena spiroides,a series of tracer experiments using P32 as a tagger has been car-ried out.Geiger Counter data from these experiments indicate that silver Carpdigests and absorbs this alga most,the Bighead (Aristichthys nobilis) ranks next andthe Grass Carp (Ctenopharyngodon idellus) the least.Certain absorption of P32 fromalgae-free media via parenteral route occurs in all 3 species,but the amount of this typeof absorption is much less than that obtained through ingestion.