The authors investigated fungal communities associated with eggs of Coregonus lavaretus holsatus species Lake Wdzydze in Kaszuby. A total of 15 fungus species were found to grow on the studied eggs: Achlya americana, A. oblongata, A. treleaseana, Aphanomyces frigidophilus, A. irregularis, A. parasiticus, Aplanes androgynus, Saprolegnia ferax, S. parasitica, S. salmonis, S. shikotsuensis, Pythium aquatile, P. pulchrum, P. thalassium, and P. torulosum. Worth a special note was the finding of Aphanomyces frigidophilus and Saprolegnia salmonis, new to Polish waters. The results obtained may be important to ichthyopathologists, because 8 of the above-mentioned fungi are known as necrotrophs or parasites of fishes.