ID help pls

[gbroadbridge]

Maybe common, but not in my tank.

Anyone tell me what could be creating these tunnels? This was dead rock so must be some hitchhiker.

 

[RedReefer]

Looks like a type of sponge.

 

[ying yang]

Sponge or tunicate is my guess

In shaded part under rocks

 

[gbroadbridge]

Thanks folks, sound harmless.

I had visions of some nasty critter hiding in the tunnels. Never had them before.

 

[G Santana]

Very cool looking sponge

 

[wonroc]

looks cool