Unlike trout, grayling are active during the day and can often be caught on small nymphs and dry caddis patterns in broad sunlight. Char prefer cold waters and are notably difficult to catch on dry flies. They often hold in the deep parts of lakes where they feed on animal plankton and insects that hatch over deep water like chironomids. Large char, that feed on fry, can be caught on streamers, but in general small, dark gnats and chironomids are the best flies. Swedish fishermen generally make a distinction between two subspieces of brown trout, the small brook trout and the larger lake or river trout.
Brook trout are extremely shy and vary, often holding under trees and in undercut banks.
These fish require perfect presentations and small flies and light tippets. Lake or river trout are opportunists that feed on insects as well as other fish, but since they are mostly active only during the night, they require extreme caution. The best way of catching trophy trout is often with dark wet flies on sink tip lines in the middle of the night. 7-weight floating and sink tip lines are often used. Hip waders are usually enough and Finnish Nokia rubber waders are especially popular, since they have sturdy boots that you can hike to the water in.