Sponge...?

[willfly4food]

Bad? It's on the bottom of a rock?

 

[Maggie321]

Probably just a sponge. Not bad. Neutral really. I'd leave it if it were in my tank. By the looks of it, your rock is fresh, all part of a healthy tank!

 

[AcroNem]

Almost looks like glue haha. It's harmless, a sign of your system starting to mature.

 

[willfly4food]

Probably just a sponge. Not bad. Neutral really. I'd leave it if it were in my tank. By the looks of it, your rock is fresh, all part of a healthy tank!

Thank u

 

[willfly4food]

Almost looks like glue haha. It's harmless, a sign of your system starting to mature.

Thank u