Any ideas?

[kgstei]

This is in a dark corner of my tank. Do you think it's a type of sponge or a soft Coral that has no coloration because of lower light. It's not in a completely dark area as you can tell by the purple sponge that's growing nearby.

 

[Joker]

It's sponge it's good for your tank and a sign of maturity.

 

[kgstei]

Thank you appreciate it