This is a relatively large lake, legendary in many ways, when the great catch and large fishes caught in the past are remembered. The lake was occupied by a natural stock of brown trout from Lake Onytavatn and its natural breeding spots are and were in the connecting river Kvislar. Sport fishing did not start until a few years ago and the lake was almost overexploited by netting. In 1994 was closed for fishing. The lake produces much food for the fishes, flies, chrysalides, worms, conches and sticklebacks. The catch was great from the windward banks. The lake is situated at the foot of the low mountain range Snjooldufjallgardur. Lake Graenavatn is situated at the foot of The Snowy Mountain Range with almost barren surroundings. It elevation is 579 m, the area is 3,3 km², the greatest depth 13,5 m, the volume 22,2 Gl, the average depth 6,8 m, the length 3 km and width 1,6 km.
The catch has been increasing steadily since 1994, 256 fishes in 1998. The most common bait is mackerel. Spinners work well and enable long throws. Fly fishing is not so successful (mainly with no. 8-10 one and two hooks and streamers). The best fishing spots:
Fjaran, Hofdavik, Gjotan, Netafjara, Botn and Raninn. Half way between Botn and Raninn, below the eastern slopes, is a deep spot, which has given some fish, even though it is not listed as a fishing spot.