You could also try a simple marabou wing streamer-- easy to throw, but it will puff up a bit in the water to look like a decent meal-- i like them because they're a cinch to tie, suspend in the water column and you can fish them real slowly over the tops of weed beds or in shallow water -- even letting them just sit for a bit in still or slow moving water. This one is a size 8, which should be easy to throw with your 3 weight.
This is also a very easy fly for any of our new tyers out there that might be looking. Here's a recipe for fly in the pic, but use whatever materials you have on hand, and tie it as fancy or as basic as you want.
Hook: streamer hook 3 or 4 extra long, size of your choice, (4xl size 8 here)
Tail (optional): A few hackle barbs from strung rooster saddle feather about a hook gape long used here. A short "tag" of red wool, tuft of rabbit fur etc are other options.
Body: Sparkle Braid, Diamond Braid, Bill's Body Braid or similar, color of your choice.
Throat (optional): A few hackle barbs tied underside of hook about a hook gape long used here.
Wing: Marabou extending to end of tail,
Flash (optional): a couple pieces cut from a single strand of pearl Krystal Flash on each side of wing used here
Topping (optional): 6 or so strands of strung peacock herl as long as wing used here. After tie in, if the herl strands are sticking out straight, you can curl the herl strands over needle of your bodkin to bend into a more natural looking curve.
Just vary sizes and colors to suit-- white wing/silver or pearl body, yellow wing/gold body, and black wing/gold body have also been good. Those colors and hot pink/pearl body are also good for crappie and perch if you have any around.