The present investigation examines prevalent fungal illnesses in fish, their etiologies, and the effects of environmental stressors. The paper examines multiple diagnostic techniques and proposes control measures to avert diseases, specifically addressing Black Gill disease (Furarium), Aflatoxicosis, Saprolegniasis, Branchiomycosis, Ichthyophonus disease, and Epizootic Ulcerative Syndrome (EUS) fungal infections in fish. Mycoses are among the most prevalent illnesses observed in temperate fish. Fungal spores are present in all fish ponds and pose issues for stressed fish. Subpar water quality may result in a rise in fungal diseases in an otherwise flourishing fish population. Most fungal infections mostly affect exterior tissues, with just a few numbers capable of infecting the interior organs of fish. Fungal illnesses in fish have gained significance over the last two decades. The conventional "fungi" consist of entities from multiple distinct taxonomic kingdoms. A growing number of environmental funguses are being documented in ill fish, further evidencing the opportunistic characteristics of several fungi.