I was over my parents house on Sunday and was checking out my brother's tank. He asked me what these weird looking things were covering his LR. At first I thought it was all red coralline that was starting to overlap and plate out. Then I saw everything moving with the current and saw there were hundreds of thousands of flatworms. Almost every square inch of LR was covered. I know there are too many for any fish or invert to handle, but thought it might be a good reason for him to add another fish anyway. I also told him to use Flatworm Exit.