Algae? ID

[jroescher]

What is this? It's not spreading, only getting bigger. The snails and crabs stripped everything else around it, but don't touch this stuff.

[mkengr45]

Don't know what it is but i have seen tons of this stuff while snorkeling in Cozumel. Its all over the rocks.

[cbianco]

jroescher

I see bubble algea towards the bottom right of your picture. The plant like algea is some sort of macro algea, kinda hard to tell in the light. The purple stuff is coraline algea.

The "half shell" stuff... I have no idea. Kinda looks like a barnacle of sorts. I am sure that this is your question. Maybe someone could fill in the gap?

Christopher

[jroescher]

The "half shell" stuff is what I'm looking at. It came on carribean rock. I just pulled a piece off and it's soft. Firmly attached. Its dark green around the top, and fades to white down in the middle.

I've got coralline algea growing in several different colors. Light and dark purple, very dark red, real light aquamarine colored, and some others.

[JimD]

Lobophora or brown wafer algae. Can be a nusience but is usualy periodic and will go away on its own in time if good water conditions are maintained. More apparent in newer systems. Keep a close eye on it, nothing I know of will eat it.