Little Yellow Stonefly Nymph

For fly fishing, stonefly nymphs are very important in fact, they are more important than the adults. The reason is that they make up a major portion of a trout’s diet. There are several species of stoneflies, but the species of the Periodidae family are the most important. Within this family, the basic color and shape does not vary much, however, there are some differences in their size.

The Little Yellow Stonefly, (Yellow Sally) is of this family and like all other stoneflies; they crawl out of the water to hatch. The migration route takes them from their home between or under the rocks on the floor of the stream to the banks where they will hatch. This action allows the trout to eat them in great numbers. As long as the little yellow stoneflies remain in or under rocks they are safe from the trout unless they become dislodged in some way and drift downstream.

Since there are so many species of stoneflies, their hatches occur often, more so than most anglers realize. Therefore, it is wise to try the stonefly nymphs almost anytime throughout the entire year especially since the trout will eat them whether or not they are hatching. The little yellow stonefly provides the best opportunity for anglers as they often hatch during the daytime hours and some may hatch during the early evenings in warm weather. Other species however, will hatch only during the evenings.

Stoneflies must have clean fast flowing waters to live. Some of the stoneflies will crawl up on the stones projecting above the water to hatch but most of them will migrate to the banks to hatch. Upon reaching the banks, they will abruptly shed their shucks and fly away. The several species of the little yellow stoneflies hatch at different times of the day with the Yellow Sally species hatching predominately in the afternoons. Warmer weather will sometimes delay the hatch to late afternoon. Although the nymphs may migrate all day, the best opportunity for the anglers will be later in the day.