The trout are stocked at a minimum weight of one and a quarter pounds with a healthy proportion of larger fish of up to eight pounds in weight and a small proportion of double figure fish. The largest rainbow, a fish of 17lb 8oz was caught in 2006 by a visiting angler using a mayfly on a floating line while fishing from a boat.

The newly stocked fish acclimatise rapidly and seem to stay high in the water with some spectacular displays of acrobatics when hooked. The new fish soon disperse around the reservoir giving both bank and boat anglers access to fish and anglers using imitative patterns prove particularly successful.

Powdermill holds native brown trout with beautifully marked specimens caught fairly frequently. The brown trout seem to prefer to feed on the bottom but can be caught at any depth. Native brown trout of over 10 lb have been caught.