Blood knot
Also called barrel knot
A blood knot is a line-to-line knot used to join two pieces of similar-diameter mono or fluorocarbon, most often leader to tippet.
- Group
- Line-to-line knots
- Category
- Knots & rigging
- Level
- Intermediate
- Water
- Fresh & salt
Last updated
What Blood knot means
Two tag ends wrap around the opposite line, then both tags pass back through the center gap. Dressed and tightened correctly, it seats into a compact, straight connection that slides through guides well.
Anglers use it to build or repair tapered leaders, add a fresh tippet section, or step down in diameter in stages. It works best when the two materials are close in diameter. If the diameters are far apart, other line-to-line knots usually seat more cleanly.
Tie it with clean wraps, wet the knot, and tighten by pulling on the standing lines while keeping the wraps from crossing. Trim tag ends close, but leave enough that they do not slip back through while the knot beds in.
Why it matters on the water
A clean blood knot keeps the leader turning over the way it should. That shows up as fewer piles of slack at the end of the cast, and better control of drift and depth.
Knowing when not to use it matters too. If the knot is forced to join very different diameters, it may fail. Picking a knot that matches the materials saves time on the water and reduces mid-fight failures.
Read next
- Double surgeon's knotA double surgeon’s knot is a quick line-to-line knot for joining two pieces of leader or tippet. It uses two wraps through an overhand loop to add grip and strength.
- LeaderThe leader is the clear, tapered line between the fly line and the fly. It turns the fly over and gives you a clean, controlled presentation.
- Tapered leaderA tapered leader is a pre-built leader that gets thinner from the fly line end to the tippet end. The taper helps transfer energy from the cast so the fly turns over and lands with less splash.
- TippetTippet is the thin, level line tied to the end of your leader. It’s the section you cut back and replace as you change flies and re-tie knots.