Are you talking about the yellow worms that kinda resemble Sarlaac's pit from Return of the Jedi? If so, I've never had an issue with those. Some fish might munch on them, but not sure which ones are more inclined and won't eat coral (wrasses, maybe).
I use cucumbes for stirring the top layer of sand. I've got a 8-12" cuke in each system with sand. I've never had any issues with them when they couldn't reach the powerheads. The mopheads seem to stay in the sand.