What does black toe nails mean?

Could be fungus: Could be dried blood....Need to really see it to make diagnosis...Visit a doc.

Black toenails: Black toe nails most commonly refer to subungual hematomas (a bruise under the nail) from trauma. Other causes of black toenails--not from trauma-- could be from severe nail fungus (rare), or from a malignancy (melanoma) --also rare-. If several nails are affected, this suggests subungual hematomas, and can be caused by bumping your foot, by running, or even wearing tight shoes (w/ tight toebox).