First, you'll need a good threading needle. I haven't been able to find one in the tackle shop for years. The only ones I've seen are flared out where you hook on the line and they do too much damage when pulled through. What I've been using is a 7" Morticians Needle that Bass Pro carries. I cut a small slit in the side of the eye the edge of a jeweler's file (I tried a lot of fine blades but none worked as well). See 1st picture.

For bullheads (I also use mine for cut anchovies on 8" leaders) you can skip the slit but you will need to cut off then retie the loop knot each time you rethread. You could also use an upholstery needle if you can find a straight one that's at least 7".

I use 20# fluorocarbon tied to a #4 short-shank treble/duplex for both stripers and halibut. I also insert a 1" piece of 50# line under the knot. See 2nd picture. You can use a little bigger hook but using heavier leader will make it harder to thread.

To thread the bait fish, you insert the needle right behind the gill, push it just under the skin and back out about a 1/2" in front of the tail. See 3rd picture. You'll probably want to wear gloves for this.

Pinch the line where it will go through the eye, hook/thread it through the eye and then pull the needle through. Keep some tension on the line to keep it from flairing out at the eye.

When the bullhead is out of the water it might slide up the leader but once it hits the water they swim down to the hook. Some guys put a half hitch around the tail -- I don't because it swims more naturally without it and the tail gets cut when you hook up.

This technique works well on mudsuckers and OK on bluegill. I couldn't make it work on anchovies or minnows (too fragile).

Hope this helps -- let me know how it works out for you.