Just a small tip for when you are facing Fiddlesticks.

TL:DR: Jungle creeps still show Fiddle's Dread debuff if he is nearby, even if you do not have vision of him.

So a while back Fiddle's passive was changed to not apply to targets which did not have vision of him. This meant that you could no longer be tipped off to his presence by the debuff showing up on your buff bar.

Jungle creeps however, tend to ignore FoW. (I assume they just have full vision of the map) So if Fiddle is near them, his passive debuff will show up. Clicking on the jungle creeps can help you determine when Fiddle is waiting nearby in ambush.

Came in very handy in my last game when I noticed my red-buff had the Dread debuff while I was clearing.