Baby brittle star?

I've had this 8gal nano for a little over three months now, and tonight after a water change I found this little guy moving across the glass. I took a video also, I'll post the link later. It appears to have 6 "arms", two of the arms are about 1.5cm and the other three are maybe 3mm.

Looking closely, I can see micro--things on each of the arms that appear to help it move across the geography. It looks like it has horizontal stripes on the arms as well. Any ideas?

 

It is indeed a brittle star (Ophiuroidea) but not a baby. Ophiuroidea do get bigger but not much bigger.

 

Yeah, basically a micro brittle star. Weird seeing one on the glass with lights on. Mine usually stay in the rockwork.

 

+1 its quite rare to see them wondering on the glass, count yourself lucky. if you look closely at your rock work you should see their arms stretching out from little caves in your rock to capture food. at night you may have the luck, as you did, to see them moving around but if you shine light on them they quickly go to hiding.

 

Thanks to everyone for their help! Now, second task:

On my DT (Not the nano) I saw these random little things growing along my filter's arm - they are also growing on the glass around the arm. They look to be about half a dime's size, and have either 5 or 6 arms reaching out. Any idea what they may be?

Please disregard the photogenic melanurus wrasse!

 

Harmless filter feeders whos name escapes me now. Common for them to grow on areas where maintenance is not thorough

 

Serpulidae if i am not mistaken

 

Yep- a species of micro-tube worm. The white specks are actually spiral tubes. They may get slightly larger, but not enough to really see anything more with the naked eye.

 

Interesting, thanks for the identification!