Pike has never been found in the lake before and could pose a threat to other fish species.
The carnivorous nature of the species puts other fish at risk. They could also carry disease and parasites.
The IFI investigation will determine if the Pike were introduced to the lake by human means. It is illegal to move fish between watercourses.
"Ireland’s inland waterbodies are ecologically important ecosystems, which support significant recreational fisheries for native and established fish species," said IFI's Chief Executive Officer, Francis O'Donnell. "‘Introductions’ of new species threaten these ecosystems that they support, potentially in unforeseen ways, and are a major cause for concern for Inland Fisheries Ireland. Unfortunately, a similar introduction of pike into the upper sections of the Owenriff catchment in County Galway over ten years ago caused the virtual collapse of what had been a very important salmon fishery in the West of Ireland."
IFI have urged anglers to protect the nation's fisheries by not moving fish between watercourses.
Anyone with information on suspicious activity are requested to call Inland Fisheries Ireland’s confidential hotline number on 1890 34 74 24.
