Â Ichthyophonus hoferiÂ and Saprolegnia, as well as certain other true fungal infections. Fungal infections are generally characterized by white, patchy, cotton-like growths on the body, mouth, or fins. Fungal infections usually occur as secondary infections from a previous wound or injury. Without treatment, fungal infections will spread and ultimately cause death. Fritz Expel-F will negatively affect Bryopsis algae growth.