Hitchhiker

Hi everyone I am new to this so I will try to explain this as best as I can.



My tank is a 30 gallon Cardiff saltwater aquarium with a Current Orbit Marine LED light. I bought some live rock (purple) and there are two things that look like feather dusters on it. When I turn off my light they go into their tube. Are they feather dusters? Also I was looking at my tank and I noticed that on the rock there is this thing that sticks out in an oddly shaped circle. When the filtration is going there is a hole in it and it opens. I turned off the filtration and the hole closed. Any input on this? Any answers are greatly appreciated.



Thanks,



Seth