What are these?

[ZR2]

I have noticed these growing on the back wall of my fluval evo 13.5 and have no idea what they are. They started off as white blobs and now have a hint of red and green coloring. I also noticed today after adding new fish and corals that there were these little brown bugs crawling on the sand in my tank. They move fast and are almost microscopic. I am not sure if I had them before I just happened to be looking at the sand bed. Could they be sand skaters? I could not get a picture of them because they are so small. 

 

 

[Joevember]

Looks like they're tube worms/feather worms. Nice to have in any system. 

The little bugs are probably copepods, hard to get pics of them since they're so small, but from the description they probably are pods.

[WV Reefer]

1 hour ago, ZR2 said:

I have noticed these growing on the back wall of my fluval evo 13.5 and have no idea what they are. They started off as white blobs and now have a hint of red and green coloring. I also noticed today after adding new fish and corals that there were these little brown bugs crawling on the sand in my tank. They move fast and are almost microscopic. I am not sure if I had them before I just happened to be looking at the sand bed. Could they be sand skaters? I could not get a picture of them because they are so small. 

 

 

Spiorbid worms.  Harmless. You can scrape them off if the population explodes.