Streamers are designed to imitate a variety of food trout eat. Minnows, bait fish, sculpin, and leeches are some of the main things.
There are two basic mistakes you can make with any imitation, especially with streamers which are more like lures than flies. One, is that you can present it such that the fish can’t see it at all or two, you can present it such that the fish get too good of a look at it. If the fish can see that it is not anything alive that they want to eat, they are not going to eat it.
Somewhere between these two extremes (can’t see it at all or see it too well) is the ideal situation.
Look at your streamer in the water close to you while it is moving through the water just like you are going to present it. Imagine that if you were a trout, would you be able to see it? If so, would you be able to see well enough to determine it was a fake? The objective is to select and present one that you can just barely see, depending on the amount of light penetration (time of day, sky conditions, cloudy, overcast or bright sunshine-clear water, stained water or muddy water).
The idea is for the trout to see it just enough to be fooled into thinking it is a real live creature it wants to eat. By the way, what works one hour many not work a few hours later. As light conditions change due to clouds, shade, etc. you should change the shade of color of your streamer to not make it very obvious but to make it just visible enough for the trout to get a glimpse of it.
Click below for a list of flies:
Mayflies
Caddisflies
Stoneflies
Midges
Streamers
Terrestrials
In the water, moving along the bottom, it looks like a sculpin.
