As useful and effective as the Swimming Nymph is, there's always been a few things missing in order to make it the perfect carp fly. One is size. A size 8 is fine for carping, but I'm talking more about bulk. The original is sleek and hackled; I want a big warm fuzzy for carp. That means rabbit and plenty of it, along iwth a chunky mid section. The next thing is weight, so adding bead chain will help get the fly down, as well as add to a broader profile in the water. The final element is rubber legs. I like the movement rubber legs give a carp fly, and so do the carp. Look at any killer carp fly and it comes equipped with rubber legs. You add in all those factors and the fly pulses, moves, breathes. Carp are very tactile when it comes to feeding, and since you lose the element of scent when fly fishing, profile and movement of the fly and the feel of a fly in the carp's mouth is what's gonna make the difference between a take and a snub.
I've tinkered with a few variations and finally came up with something that I feel will work best for carp. Rabbit tail, beefy dubbed body, large pheasant hackled thorax, rubber legs, large bead chain eyes, and a bushy rabbit throat. I still maintained the classic signatures of the original swimming nymph with peacock herl and rust colored body, and still maintain a similar gestalt to the profile of the original. I think I've found the right balance for an Improved Swimming Nymph.
Now it's only a matter of time to see what the carp think.