A test was conducted to evaluate the effect of two invertebrates, Asellus militaris Hay and Gammarus pseudolimnaeus Bousfield, on the growth of fungus, Saprolegnia sp., on walleye eggs, Stizostedion vitreum vitreum (Mitchill). In a second test the effect of the two invertelbrates on mortality of white sucker fry, Catostomus commersonnii commersonnii (Lacépède), was ascertained. Egg mortality was 100% where fungus was not controlled. Both Asellus and Gammarus eliminated fungus‐related mortality. Gammarus caused about 15% mortality for both eggs and fry. Asellus did not cause mortality for either stage.