Nov 19, 2013 #1 J Jerinanyon Aquarium Advice Activist Joined Sep 26, 2013 Messages 117 What is growing on my rocks. This started 3 days ago. Attachments image-2172733918.jpg 213.4 KB · Views: 81
Nov 19, 2013 #2 Bectan01 Aquarium Advice Addict Joined Aug 21, 2012 Messages 1,930 Location melbourne, australia It looks like cyano to me