Catgut Biothread

(3 customer reviews)

US$3.56

  • One of the best materials for tying killer, super-realistic nymphs.
  • Unique and versatile – a top choice material among the world’s most experienced fly tyers.
  • It is opaque, solid-colored when dry, and becomes milky translucent and shiny when wet.
  • When submerged in water, it becomes very soft, flexible, and stretchable, which makes it super easy to work with.
  • As it soaks in water, its volume also increases, giving a plump appearance to the fly.
  • The most amazing benefit of using this material is the way it looks in water – flies tied with it look extremely authentic, have lifelike texture, and super-high shine.
  • The material has been treated to extend its durability under water.
  • To apply, soak the part you want to use in warm water for 3-5 minutes prior to tying. The color will change from opaque to more milky and transparent and the material will be super-flexible and easy to wrap.
  • When the fly dries, the body will go back to its solid-colored state.
  • By using various colored threads underneath it for the underbody, different effects can be achieved as the color peaks through the wet material.
  • About 50 cm long (about 20”), comes in four diameters and a wide range of colors.
  • Sizes (Diameters) and hook recommendations:
    • Extra Small (0.18mm) – for hooks #16 and #20
    • Small (0.3mm) – for hooks #14 and #16
    • Medium (0.5mm) – for hooks #12 and #14
    • Large (0.7mm) – for hooks #8 and #10
  • Absolutely perfect for making bodies for nymphs and emerger flies.
  • Also a great choice material for making loops on traditional salmon flies (small diameters, in particular, XS and S)
  • See the Description section below for more details, tying instructions, and more!
ImageSKUColorSizePriceQuantityAdd to Cart
Catgut Biothread - Natural SKU: 107-0114XS-01Color: NaturalSize: Extra SmallPrice: US$3.56
Catgut Biothread - Natural SKU: 107-0114SM-01Color: NaturalSize: SmallPrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Natural SKU: 107-0114ME-01Color: NaturalSize: MediumPrice: US$3.56
Catgut Biothread - Natural SKU: 107-0114LG-01Color: NaturalSize: LargePrice: US$3.56
Catgut Biothread - Brown SKU: 107-0114XS-02Color: BrownSize: Extra SmallPrice: US$3.56
Catgut Biothread - Brown SKU: 107-0114SM-02Color: BrownSize: SmallPrice: US$3.56
Catgut Biothread - Brown SKU: 107-0114ME-02Color: BrownSize: MediumPrice: US$3.56
Catgut Biothread - Brown SKU: 107-0114LG-02Color: BrownSize: LargePrice: US$3.56
Catgut Biothread - Cocoa Brown SKU: 107-0114XS-03Color: Brown CocoaSize: Extra SmallPrice: US$3.56
Catgut Biothread - Cocoa Brown SKU: 107-0114SM-03Color: Brown CocoaSize: SmallPrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Cocoa Brown SKU: 107-0114ME-03Color: Brown CocoaSize: MediumPrice: US$3.56
Catgut Biothread - Cocoa Brown SKU: 107-0114LG-03Color: Brown CocoaSize: LargePrice: US$3.56
Catgut Biothread - Caddis Green SKU: 107-0114XS-04Color: Caddis GreenSize: Extra SmallPrice: US$3.56
Catgut Biothread - Caddis Green SKU: 107-0114SM-04Color: Caddis GreenSize: SmallPrice: US$3.56
Catgut Biothread - Caddis Green SKU: 107-0114ME-04Color: Caddis GreenSize: MediumPrice: US$3.56
Catgut Biothread - Caddis Green SKU: 107-0114LG-04Color: Caddis GreenSize: LargePrice: US$3.56
Catgut Biothread - Cinnamon SKU: 107-0114XS-05Color: CinnamonSize: Extra SmallPrice: US$3.56
Catgut Biothread - Cinnamon SKU: 107-0114SM-05Color: CinnamonSize: SmallPrice: US$3.56
Catgut Biothread - Cinnamon SKU: 107-0114ME-05Color: CinnamonSize: MediumPrice: US$3.56
Catgut Biothread - Cinnamon SKU: 107-0114LG-05Color: CinnamonSize: LargePrice: US$3.56
Catgut Biothread - Fluo Pink SKU: 107-0114XS-06Color: Fluo PinkSize: Extra SmallPrice: US$3.56
Catgut Biothread - Fluo Pink SKU: 107-0114SM-06Color: Fluo PinkSize: SmallPrice: US$3.56
Catgut Biothread - Fluo Pink SKU: 107-0114ME-06Color: Fluo PinkSize: MediumPrice: US$3.56
Catgut Biothread - Fluo Pink SKU: 107-0114LG-06Color: Fluo PinkSize: LargePrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Fluo Yellow SKU: 107-0114XS-07Color: Fluo YellowSize: Extra SmallPrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Fluo Yellow SKU: 107-0114SM-07Color: Fluo YellowSize: SmallPrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Fluo Yellow SKU: 107-0114ME-07Color: Fluo YellowSize: MediumPrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Fluo Yellow SKU: 107-0114LG-07Color: Fluo YellowSize: LargePrice: US$3.56Out of Stock
Out of Stock
Catgut Biothread - Green Olive SKU: 107-0114XS-08Color: Green OliveSize: Extra SmallPrice: US$3.56
Catgut Biothread - Green Olive SKU: 107-0114SM-08Color: Green OliveSize: SmallPrice: US$3.56
Catgut Biothread - Green Olive SKU: 107-0114ME-08Color: Green OliveSize: MediumPrice: US$3.56
Catgut Biothread - Green Olive SKU: 107-0114LG-08Color: Green OliveSize: LargePrice: US$3.56
Catgut Biothread - Olive SKU: 107-0114XS-09Color: OliveSize: Extra SmallPrice: US$3.56
Catgut Biothread - Olive SKU: 107-0114SM-09Color: OliveSize: SmallPrice: US$3.56
Catgut Biothread - Olive SKU: 107-0114ME-09Color: OliveSize: MediumPrice: US$3.56
Catgut Biothread - Olive SKU: 107-0114LG-09Color: OliveSize: LargePrice: US$3.56
Catgut Biothread - Olive Brown SKU: 107-0114XS-10Color: Olive BrownSize: Extra SmallPrice: US$3.56
Catgut Biothread - Olive Brown SKU: 107-0114SM-10Color: Olive BrownSize: SmallPrice: US$3.56
Catgut Biothread - Olive Brown SKU: 107-0114ME-10Color: Olive BrownSize: MediumPrice: US$3.56
Catgut Biothread - Olive Brown SKU: 107-0114LG-10Color: Olive BrownSize: LargePrice: US$3.56
Catgut Biothread - Orange SKU: 107-0114XS-11Color: OrangeSize: Extra SmallPrice: US$3.56
Catgut Biothread - Orange SKU: 107-0114SM-11Color: OrangeSize: SmallPrice: US$3.56
Catgut Biothread - Orange SKU: 107-0114ME-11Color: OrangeSize: MediumPrice: US$3.56
Catgut Biothread - Orange SKU: 107-0114LG-11Color: OrangeSize: LargePrice: US$3.56
Catgut Biothread - Red SKU: 107-0114XS-12Color: RedSize: Extra SmallPrice: US$3.56
Catgut Biothread - Red SKU: 107-0114SM-12Color: RedSize: SmallPrice: US$3.56
Catgut Biothread - Red SKU: 107-0114ME-12Color: RedSize: MediumPrice: US$3.56
Catgut Biothread - Red SKU: 107-0114LG-12Color: RedSize: LargePrice: US$3.56
Catgut Biothread - Yellow SKU: 107-0114XS-13Color: YellowSize: Extra SmallPrice: US$3.56
Catgut Biothread - Yellow SKU: 107-0114SM-13Color: YellowSize: SmallPrice: US$3.56
Catgut Biothread - Yellow SKU: 107-0114ME-13Color: YellowSize: MediumPrice: US$3.56
Catgut Biothread - Yellow SKU: 107-0114LG-13Color: YellowSize: LargePrice: US$3.56

Catgut Biothread

Catgut Biothread is one of the best materials for tying extra effective, super-realistic nymphs. Its very unique characteristics and versatility make it a top choice among the world’s most experienced fly tyers. This material is opaque, solid-colored when dry, and becomes milky translucent and shiny when wet. When submerged in water, it also becomes very soft, flexible, and stretchable, which makes it super easy to work with. As it soaks in water, its volume also increases, giving a plump appearance to the fly. The most amazing benefit of using this material is the way it looks in water – flies tied with it look extremely authentic, have lifelike texture, and super-high shine. The material has been treated to extend its durability underwater.

To apply, soak the part you want to use in warm water for 3-5 minutes prior to tying. The color will change from opaque to more milky and transparent and the material will be super-flexible and easy to wrap. When the fly dries, the body will go back to its solid-colored state. By using various colored threads underneath it for the underbody, different effects can be achieved as the color peaks through the wet material. The combinations are really limitless. See below for detailed instructions.

Catgut Biothread is about 50 cm long (about 20”), comes in four diameters, and wide range of colors.

Sizes (Diameters) and hook recommendations:

  • Extra Small (0.18mm) – for hooks #16 and #20
  • Small (0.3mm) – for hooks #14 and #16
  • Medium (0.5mm) – for hooks #12 and #14
  • Large (0.7mm) – for hooks #8 and #10

Catgut Biothread is perfect for making bodies for nymphs and emerger flies. It is also a great choice material for making loops on traditional salmon flies (small diameters, in particular, XS and S)

How to use Catgut Biothread

Tying a Classic Micro Nymph with Catgut Biothread

Tying the Micro Nymph with Catgut - Final Fly - Wet

TYING A CLASSIC MICRO NYMPH

with Catgut Biothread

First Step

Prior to tying, soak the part of Catgut Biothread that you want to use in warm water for 3-5 minutes. The color will change from opaque to more milky and transparent and the material will be super-flexible and easy to wrap. When the fly dries, the body will go back to its solid-colored state.

Tying the Micro Nymph with Catgut - Step 1
Tying the Micro Nymph with Catgut - Step 2
Tying the Micro Nymph with Catgut - Step 3
Tying the Micro Nymph with Catgut - Step 4
Tying the Micro Nymph with Catgut - Step 5
Tying the Micro Nymph with Catgut - Step 6
Tying the Micro Nymph with Catgut - Final Fly - Dry

Finished Micro Nymph with dry body

Tying the Micro Nymph with Catgut - Final Fly - Getting Wet

Micro Nymph after a few seconds of soaking in water

Tip

By using various colored threads for underbody, different effects can be achieved as the color peaks through the wet material. The combinations are really limitless.

Tying the Micro Nymph with Catgut - Final Fly - with Green Underbody thread

Micro Nymph with green underbody thread

Tying the Micro Nymph with Catgut - Final Fly - with Green Underbody Thread - When Wet

Micro Nymph with green underbody thread - soaked

Tying the Micro Nymph with Catgut - Final Fly - with Brown Underbody Thread

Micro Nymph with brown underbody thread

Tying the Micro Nymph with Catgut - Final Fly - with Brown Underbody Thread - When Wet

Micro Nymph with brown underbody thread - soaked

Video Tutorial

Fly Tying a Catgut Caddis Pupa

For a full list of ingredients for this recipe, go here. 

Weight 0.005 kg
Dimensions 13 × 7 × 0.3 cm
Manufacturer

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3 reviews for Catgut Biothread

  1. Jeff

    This is an absolute must have product. A real game changer on the hook once wet. Quick soak in warm water before tying and it applies like dream. Sells out quickly, so get your order in.

  2. Robert Spangler (verified owner)

    Great material for segmented body.

  3. K Rentzheimer (verified owner)

    I’ve been waiting for a few years to tie with cat gut. But every time I went to order it was sold out. Finally purchased in the Olive green and Natural. All I can say is WOW! Simple tie and when wet looks fantastic. Pleasantly surprised. Will be buying more.

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