I have about three apparent yellow sponges growing adjacent to some xenia. The sponges seemed to have just grown out of nowhere a few months ago.
How big can they get? The one in the pic (which happens to be the largest one) is only about 2cm in length. A couple of smaller xenia stalks seem to be growing from under it:
What are some do's and don'ts in regards to caring for them? I presume I'm not to expose them to air, but other than that they appear to be doing fine on their own.
How big can they get? The one in the pic (which happens to be the largest one) is only about 2cm in length. A couple of smaller xenia stalks seem to be growing from under it:

What are some do's and don'ts in regards to caring for them? I presume I'm not to expose them to air, but other than that they appear to be doing fine on their own.