What is this stuff?

[infanterene]

In my Nano tank I have this stuff that looks like lint, it is white or grey in color. Its on the rocks. What is it?
In my 55 which just finished cycleing i have this green slime on the rocks. It has just started. What is it?
Should I be worried?

 

[otto13]

I have the same stuff in my nano. It sticks up about 18 of an inch. Looks like a type of macroalgae. My hermits are eating it. If it is on the glass, check and see if it moves. Watch it for a minute or two. Probably a little amphipod. "Seabug" They eat algae too. Harmless.
You will probably get alot of green and brown algae. Get a cleaner crew of astrea snails and red legged hermits.