There is not a time of year when you can't use  nymphs to catch trout, panfish and and even bass. Some nymphs, like Hellgrammites, the larval form of dobsonflies,  may live as long as three years in the water before they hatch into winged adults. This means that at any given time there are these nymphs present in streams, lakes and ponds.

These are un-weighted, tied on Japanese streamer hooks.

Fly length, including tail and antenna, 1.5 inches.