Why locals love it
Fylgifiskar (e. follower, adherent) is extremely popular among locals during lunch time because it's really cheap considering other seafood restaurants in Reykjavík. During lunch time you can choose from three main courses and believe me, you won't be disappointed with the variety and also the taste!
Why you should visit it
The restaurant is situated in the area of the financial industry, so prepare to stumble upon the famous Icelandic yuppies that made Iceland great before the financial crisis in 2008. Anyways, the place itself is rather plain and the interior design does not try to be more than it is. The staff is extremely friendly and the atmosphere is relaxed.
If you are able to cook fish at your own accomodation, you can buy prepared fish in Fylgifiskar and cook it yourself. It's cheaper!