Definitely a heterotroph. They cannot make their own food by photosynthesis, so they cannot be autotrophs. They feed off of living or dead plant or animal (or other organism) matter by excreting enzymes that digest the material outside the body of the fungus and then absorb the digested matter through their hyphae.
heterotroph
heterotroph
Heterotroph
Heterotroph.
heterotroph.
Heterotroph
Heterotroph.
heterotroph
heterotroph
Autotroph
autotroph
Autotroph