My fishing buddy & I have been fishing an oxbow, and have been having success using Glenn Ueda's LocoMoco fly: Tail is an alternating yellow/brown foam discs punched out from arts & crafts 2mm foam sheets. I believe the tail is the trigger for the carp. The body is a dubbing loop of Ice Dub, but you'll have to experiment what the carp like in your home waters.

When carp are tailing or mudding (unseen) in the oxbow, they give away their position because you'll see the water turn black. I've had success by casting into/around the mud boils. Some will take it on the drop, and some while the fly is being scooted into/around the strike zone. I lost a decent-sized fish (saw humungous tail), when I was trying to horse it in, along with too much upward pressure. Lessons learned. Tight lines!