Does anybody know what this is?

[ste76]

Hi, has anyone seen this before and if so what is it?

Thanks guys

 

[Oscarr19]

It's a sponge, nothing to worry about.

 

[ste76]

Oh ok, thank you for such a quick answer. Do you know who big it is likely to grow? I'm new to salt water. I'm learning every day and loving it.

 

[bribo12]

It won't get very big, sponges are filter feeders so they grow according to available dissolved organic available in the water column. It will probably stay around that size.