sponge or monster?

[Mastiffsrule]

I just wanted to be sure what I have growing all over the tank is a sponge and not something nasty. They are all over my 180 and have been growing over the past 3 years.

Thanks

 

[peasofme]

looks like sponge

 

[Betta132]

Sponge. I've had those before.

 

[rssjsb]

Probably not a monster. However, if you hear any strange singing in your sleep, you should probably call someone.