what is this

Came in on some coral. Sorry about the poor video. It is tiny and was really hard to keep it in frame. Good or bad? Do I need to try to find it and get it out? Thanks! If you can't see the video, let me know. I'm new at posting videos on Youtube.

Hello, I am cycling my tank and I am now getting some algae growth on the glass. Is this the same thing as diatoms? Or maybe the beginning of coralline algae? Should I clean it off the glass or leave it? I will attach a picture.

Hello, a friend of mine has a setosa and would like to know about these little antennas sticking out of the coral. They move in the flow and retract on contact, like a feather duster. Are they any reason to be concerned or to dip the coral? Could they cause the polyps to not extend fully...

I see like a brownish translucent spot right between eyes of my yellow tang and I’m worried it might be something I need to worry about or is it normal