Orange film

[reef_dee]

Established tank, about 13 months old. Started getting orange film on just one rock. Film is hard to remove. What is this and how I get it under control.

 

[Rtaylor]

Looks like a sponge. Normally harmless, but it looks like it’s crowding your zoas/paly’s. You’ll probably need to scrape it off with a razor blade or something similar. Make sure to wear gloves and safety glasses since you’ll be working around the zoas.