oh well I tried, it is a species of Lyngbya, species level identification requires a microscope, but it is pretty common, spread like wildfire etc.. With enough hermits, (sea hares like it too, -depending on species - next time try a ragged sea hare- but adding a sea hare isnt a decision that should be taken lightly, they need expert care - don't like powerheads, will nasty your tank when they die, very prone to salinity changes and ink, etc... - plus they dont like to clean near corals because of the stinging thing), you can wipe it out. Nerite and ceriths eat it as well, but they dont seem to be able to keep up with its growth. It is a species of cyanobacteria, just not the species of cyano everyone is familiar with. There is a great deal of diversity in cyanobacteria, a few 1000 different species, and Lyngbya is one of the more prevalent forms both in nature and in our tanks. You might be able to google it, try Lyngbya majulsca.
I would still love to be able to use the picture.
