Weird Stuff In My Aquarium

[Nano]

If your talking about the fuzzy stuff to me it just looks like detritus. I got some bad rock and I would blow it off then a day or so later it would be back. Try testing your water for phosphates with the light out at night after its been out for a few hours. If the tanks new, and you got the rock second hand sometimes it has a pretty bad build up of crud in it.

Mind you I could be 100% wrong and it could be something else. But to me it looks similar to what I had before I started getting green hair algae problems in my tank. Hopefully others will chime in with opinions