Wolfman, I dug a pond in red clay as well. The runoff into the pond carries way more clay particles than one would first think. Look around the shoreline for obvious erosion and address the issue there first. I created a rip-rap buffer where this was occuring on my pond and as the water flows into this area, it slows down and drops a lot of mud before running into the pond. Eventually it will fill in, but it'll take a while. If you can go uphill and create low terraces or obstacles, and get a good grass stand in those areas, it will go a long way to solving your problem. I'm in Clay County, TX and the county wasn't named for the soil type, but it is extremely fitting.
I can only speak from my own experience, and your results may vary. Have you added any organic materials to the pond? I add grass clippings occasionally, and older ranchers in the area use hay bales to kickstart the transition from a hole in the clay to being a pond.
Keep after it, you'll learn a lot on this forum and trying new things with the pond.
