The Isla is the Tay's largest tributary and one of Scotland's hidden salmon rivers — a substantial water in its own right that drains Glen Isla, Strathmore, and the rich farmland north of Dundee before joining the Tay at Kinclaven. The upper river in Glenisla above Forter is tumbling Highland water holding brown trout and the occasional summer salmon. The middle river through Strathmore is classic lowland fly water: broad, pebbly, with good holding pools and fine brown trout fishing through the traditional season. The lower reaches below Coupar Angus hold resident trout, grayling, and salmon that have pushed up from the Tay, particularly in autumn. Fishing is a mix of Blairgowrie, Coupar Angus and Strathmore angling associations on the middle and lower river, with private beats scattered throughout. A proper big-river tributary that deserves more attention than it receives — and would certainly receive it were it not overshadowed by its famous parent.

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