Is this a sponge?

[A4_Andre]

Tried to research this online but did not have much luck and assumed it was a sponge based on what I did find. The one in the pic broke free and was like an aquatic tumbleweed so i decided to scoop it up. It does feel like it could be a sponge. Should worry about this or can I put it back in my tank? Thanks in advance!

 

[arnaldolex]

i would say yes

 

[salpet]

its definitely a sponge