When does fungus becomes a mold?
A mold is a type of microscopic fungi that grow in the form of multicellular filaments ( branching structures), called hyphae. In contrast, microscopic fungi that grow as single cells are called yeasts. So to answer your question molds are always molds. The only way that a mold fungi changes is during reproduction when they produce spores which gives the mold that fuzzy appearance you might see on decaying fruit and bread. Also mold fungus is only visible to the human eye when they grow in colonies which are interconnected by a network of hyphae called a mycelium. Not all Fungus is mold which the above persons stated. Mold Fungus belong to the fungi divisions Zygomycota, Deuteromycota and Ascomycota.
