What’s this?

[StPatrick89]

Cleaning my tank, seen this on the shell of my crab. It’s hard and won’t come off.

 

[T-J]

Looks like a feather duster tube.

 

[Isopod80]

+1 looks like one of the small colonial varieties with the white crowns. I have a bunch on some of the rockwork in my tank. Harmless filter feeders. I like them. They're just another organism to add some realism to the overall look of the tank.

 

[StPatrick89]

+1 looks like one of the small colonial varieties with the white crowns. I have a bunch on some of the rockwork in my tank. Harmless filter feeders. I like them. They're just another organism to add some realism to the overall look of the tank.

Thanks