Want to have fun catching the biggest fish? Tie on a mouse pattern
There are numerous mouse patterns, but most aren’t very good. They tend to be needlessly complicated and worse, they often imitate a human conception of a mouse, not what the fish see. A mouse fly just needs a mammalian profile, and to give the impression of something that’s alive and struggling. Materials that wiggle in the water are good; adding eyes, ears, whiskers and a nose is merely gilding the lily.
The best pattern I’ve found is the Morrish Mouse (pictured above). It cleverly uses mousey-looking deer hair and rabbit for the parts the fish can see, with a foam strip on top for flotation. The foam also extends forward to give the fly an erratic, sputtering action, both when drifted and retrieved. It’s also a basically indestructible fly.