There are several chemical solutions that claim to kill the red slime without bother fish and inverts. I used Chemi-Clean and it killed the algae in 2 days with no apparent harm to anything else, and I have fish, shrimp, snails, crabs, soft corals, and an anemone. IMO you should try the traditional methods first, but if they fail, Chemi-Clean worked for me and my LFS recommended it because they had successfully used it many times themselves.