Some anglers “over rig” for cobia, and that can cost them fish.
Cobia have no sharp teeth, so wire leaders are unnecessary. But the fish do have small, abrasive, sandpaper-like teeth that can fray even heavy monofilament during a long fight. Also, cobia are a hard-fighting, tough-skin fish, and they have sharp spines along the back – all of which can abrade line. So a well-designed “shock leader” system is needed for cobia.For most cobia fishing it’s smart to double the terminal end of the fishing line with a Bimini Twist or Spider Hitch. Twenty or 30-pound test line (braid preferred) is good for most cobia fishing, and a double line four to six feet long is advised.
Some anglers tie the double line to a top-quality, black, ball bearing barrel swivel, which is advised if a sinker is used to take baits deep, since a swivel keeps a sinker above and away from a bait. Also, for trolling, the use of a swivel is needed to prevent line twist. Some baits, like eels for example, also have an annoying habit of twisting round-and-round while fishing, and that can cause disturbing line twist, so a swivel always should be placed in the terminal rigging with some baits.
A shock tippet of “hard” monofilament or flurocarbon of 50- to 100-pound test, about six-feet long, is good for cobia fishing. It can be tied directly to a barrel swivel, or it can be fastened to the doubled fishing line with a Surgeon’s Knot, Albright Knot or Uni-Knot.
Tie the heavy shock tippet to the bait hook or lure with a Palomar Knot or a 3-wrap Clinch Knot, and the terminal rig is ready for a go at cobia.