Litlaá in Kelduhverfi is a spring-fed river, which originates from springs called Brunnar near the Keldunes farm. From 1976 it also has its source from Lake Skjálftavatn that formed during a landslide in the Krafla-fires. The water from Brunnar is unusually warm and blends with the colder water from Skjálftavatn, so the average temperature of the water in the river is 12° C. Under these conditions the growth rate of fish in Litlaá is rapid and the river’s trout population is therefore one of the largest in the country. In addition to sea trout and resident brown trout, some sea-run char are caught and it is also possible to catch salmon in Litlaá. The average catch in the river is about 1500 fish, but Skjálftavatn alone gives about 600 – 800 fish.