Fiddlesticks Runes explained
There's one set of runes for Fiddlesticks on patch 14.20 that is the clear favorite for LoL players and pros alike. The best Fiddlesticks rune paths on the position 
Support are 
Resolve as the primary path and 
Domination as the secondary path with a pick rate of 83%. Besides picking runes on Fiddlesticks you should learn how to play Fiddlesticks and if you are interested in pro matches take a look on how a pro builds Fiddlesticks. If you want to discuss 
Fiddlesticks then you should visit the champion subreddit.
Fiddlesticks runes from primary path
Resolve empowers the survivability of Fiddlesticks and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that Aftershock is the best keystone rune to run on Fiddlesticks. This keystone rune bulks you up, increasing both armour and magic resistance, once you immobilized a champion. Aftershock synergises both with the sheer amount of crowd control Fiddlesticks possesses and the need to be tanky as soon as you engage. Other primary runes on Fiddlesticks are Demolish, Bone Plating and Overgrowth.
Demolish increases your pressure on the enemy turrets. This rune will help you to punish bad roams or backtimings of your lane opponent. Bone Plating make Fiddlesticks overall tankier, by decreasing the amount of poke damage in the early game. Overgrowth increases your maximum amount of health.
Fiddlesticks runes from secondary path
When it comes to your secondary path, most Fiddlesticks players prefer to go with Domination. Domination improves burst damage and assassination tools on Fiddlesticks. On the Domination path, the best runes for Fiddlesticks are 
Ultimate Hunter and 
Cheap Shot.
Ultimate Hunter scales up Fiddlesticks ultimate haste on every unique champion takedown. Cheap Shot makes you deal more damage to enemies with impaired movement, which has great synergy with the setup of Fiddlesticks.
FAQ for Fiddlesticks Runes
Which is the best keystone rune on Fiddlesticks?
The best keystone rune on Fiddlesticks is Aftershock. This Fiddlesticks runes setup is then referred as Fiddlesticks Aftershock.
What runes does Fiddlesticks use?
Runes from the paths Resolve and Domination are the most used runes on Fiddlesticks. For the exact pick rates of Fiddlesticks runes used, you have to study the rune distribution presented.