Cross-border limestone lake famous for its unique endemic trout phenotypes — gillaroo, sonaghan, and ferox — each with distinct feeding behaviour and appearance. The gillaroo feeds on snails on the lakebed; the sonaghan is a pelagic feeder. Salmon also run through. Drained by the Drowes river. One of Europe's most genetically important freshwater fish sites. The trout are fighters and the fishing is often difficult, but the setting and the fish make this a pilgrimage for knowledgeable anglers. Salmon also run the lough — spring salmon February to May, grilse from May to July. The trout phenotype experience (gillaroo, sonaghan, ferox) is the headline, but the salmon component is real and FII-documented. For 2026 this remains an open fishery — salmon may be retained in season under the Wild Salmon & Sea Trout Tagging Scheme and bag limits, with catch-and-release at other times.
- Lough system
- Limestone
