I have a new saltwater tank with just snails and crabs. I have 3 live rocks and one of them has a smooth green/yellow stuff growing on it, it looks like guacamole. Is it just algae or something I need to fix ASAP. If I need to fix what do I need to do. I have attached a pic hope you guys can see it in the pic.
75gal
Fluval filter
Live sand
Live rock
75gal
Fluval filter
Live sand
Live rock