The only time I ever heard the word was over fifty years ago, visiting my mother-in-law, who was Pennsylvania-Dutch. After lunch, she said she would "redd up the table."

P.S. When I first posted, I had not seen Today's Word. The use of "redd" for fish spawning areas seems obvious to me. I have watched sunfish work very hard to agitate water where they are about to spawn, to clear away the accumulated algae debris that would prevent fertilized ova getting adequate oxygen.