This has got to be one of the top 5 easiest fly patterns of all time. It is super quick, durable, and catches it’s fair share of fish. A true “Guide Fly”.
Caddis larva are available to trout year round. The Green Rock Worm caddis imitation has very few steps, and is a very easy fly pattern to tie. It can be used as a searching nymph, or to match the available food types in a given stream. It is bright and catches the attention of fish, so it can be used effectively as a lead fly in a tandem nymph rig to attract the fish that often will then take the small trailing realistic pattern. However, don’t let that fool you. This pattern represents free-living caddis and takes picky trout on very tough rivers. Here in Utah, Provo River fly fishing guides often tie up and fish this pattern because it is so easy and so effective.
The Lower Provo can be a very tough fishery. As the summer rolls along the fish become more and more educated and the pickier they seem to become. Often times guides switch to drab natural nymphs, and that regularly gets the job done. However, despite being bright and flashy, quite often I have found this green rock worm fly pattern to be the fly of choice. As trout catch onto fishermen and their fly patterns, I have found that my success rate goes up when fishing the smaller sizes 18-20. Go figure!
Take a few minutes and check out this fly tying video. This is a go-to caddis larva fly pattern that belongs in your box. Let us know of your success and FISH ON!
Hook: Dai-Riki 135 (Scud Hook) 14-20
Bead: Gold to match hook size: 14: 7/64″, 16: 3/32″, 18 and 20 5/64″
Thread: Uni 8/0 Olive
Rib: 4X monofilament
Body: Caddis Green Ice Dubbing
Collar: Black Hare’s Ear Dubbing
In almost every river or stream that I have ever sampled for aquatic inverts I have found multiple species of caddis larva. However much we all love to fish the beautifully tied mayfly and stonefly nymphs, caddis larva make up a huge portion of a trout’s diet. There are many imitations out there, but the Czech Nymph is my go-to caddis larva. Not to mention that it can double for a cranefly larva, or any other grub style invertebrate that finds itself floating down a trout stream.
You can tie this pattern in a multitude of color variations, either as natural, or as flashy as you desire. The tan-pink-brown variation is usually the first Czech Nymph I tie on. I prefer to fish if in sizes 8-14 with sizes 8 and 10 being the most common. Tungsten and lead are a necessity if you are euro nymphing/czech nymphing. It’s not a bad idea to have a few tied with brass beads, or no bead at all for those shallow small streams that have willing to eat big flies. Also, you can add Net Back Foil to this fly if you really want the segments to “pop”.
The Provo River has some fantastic fish that love to gorge themselves on caddis larva. One unforgettable summer day on the middle Provo, Kohler and I found ourselves scoring into some fine fish while fishing both woven nymphs, and Czech Nymphs. If you watch closely in this video you will see this color variation hanging out of the mouth of a very fine brown trout.
Hook: Dai-Riki 135 Sizes 8-14
Bead: Tungsten or Bronze Size 1/8″-7/64″ (Depending on hook size)
Underbody: 0.020 Lead Wire
Thread: 6/0 Uni Color – Camel
Backing Material: Clear Scud Back
Rib: 3X Monofilament
Body: Tan Hare’s Ear
Hot Spot: Pink Shrimp Sow-Scud
Collar: Natural Brown Squirrel