A multi-agency investigation is underway.
There's been a "significant" fish kill in Cavan.
More than 4,500 fish have been found dead in the Cavan town river.
Inland Fisheries Ireland says its officers received a hotline report on Tuesday night.
Upon arrival yesterday morning, they found thousands of dead fish over a 2km stretch of the Cavan town river.
Early indications suggest more than 4,500 trout, coarse fish and eels have died.
IFI says it's too early to definitively establish the cause, but a multi-agency investigation is underway.

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