Gynon sits high on the moor above the Elan valley, one of the natural lakes that comes bundled into the same day ticket as Claerwen Reservoir — buy the one permit and you've got both. It's fly-only water and the wild browns run to a fairly consistent size, nothing spectacular but nothing to sneer at either, the kind of steady fish that makes for an honest afternoon rather than a fish-of-a-lifetime story. The setting does a lot of the work here — big sky, bare hillside, water that colours up fast in weather and clears just as fast. Worth building a day around, especially if you're already ticketed for Claerwen and fancy a change of scenery.

• Lake
• Silurian mudstone shale