A ghillie or boatman is strongly recommended to anglers unfamiliar with the lake.
Gillaroo trout
Lough Melvin is home to the gillaroo or Salmo stomachius, a species of trout which eats primarily snails. The name "gillaroo" is derived from the Irish languageGiolla Rua, which means "Red Fellow". This is due to the fish's distinctive colouring. It has a bright buttery golden colour in its flanks with bright crimson and vermillion spots. The gillaroo feed almost exclusively on bottom living animals (snails, sedge fly larva and freshwater shrimp) with the exception of late summer when they come to the surface to feed and may be caught on the dry fly.[8]
Sonaghen trout
The sonaghen trout (Salmo nigripinnis) is another species of salmonid unique to Lough Melvin. It can have a light brown or silvery hue with large, distinctive black spots. Its fins are dark brown or black with elongated pectorals. Sonaghen are found in areas of open, deep water, where they feed on mid-water planktonic organisms such as water fleas (Cladocera), midge (chironomid) pupae and phantom (Chaoborus) larvae. Sonaghen will be most readily located close to the surface over deep water. Fly-fishing with a team of wet flies fished in classic lough style (i.e. short, snappy casts from a boat drifting beam-on to the breeze) gives best chance of success. Sonaghen give a powerful and energetic fight out of all proportion to their size.[9]
Ferox trout
The classic work carried out by Andrew Ferguson of Queens University on the genetics of the trout of Lough Melvin identified the ferox as a separate subspecies. The fish home to a specific spawning area and are reproductively isolated. They are also one of the oldest trout races to colonise Ireland, perhaps as old as 50,000 years. Ferox cannibalise brown trout (which returned to many of the same lakes when geological processes and climatic conditions allowed) and also prey on other fish species. The best method of capture is trolling, particularly with a Rapala type lure.[10]
^"Lough Melvin"(PDF). Sampling Fish for the Water Framework Directive – Lakes 2008. The Central and Regional Fisheries Boards. 2008. Retrieved 1 June 2021.
Pedreschi, D.; Kelly-Quinn, M.; Caffrey, J; O'Grady, M.; Mariani, S.; Phillimore, A. (2014), "Genetic structure of pike (Esox lucius) reveals a complex and previously unrecognized colonization history of Ireland", Journal of Biogeography, 41 (3), Journal of Biogeography, 41(3), 548–560.: 548–560, doi:10.1111/jbi.12220, PMC4238397, PMID25435649