Due to connection with Markarfljót, River Affallið was previously very glacial, but after the loading of fortifications at Markarfljótsaurum, it has changed a lot for the better and the river is now as spring-fed river. Salmon is farmed in Affallið and about 700 – 800 salmon are caught there every year, many of which are big salmon. The best-known fishing spots are Kanastaðahylur # 60, the upper release pond, and # 10, which is the lower. In addition, sea trout have always entered the river and char are also found there to a limited extent. In 2020, 1728 salmon were caught in Affallið and the river had the third highest catch in the country.