what is this?

[kimichan]

simple easy one, but no pics. i got these black bubbles forming all over my live rock. maybe 1/4 inch in diameter. they are semi flexible, and my girlfriend popped one without asking me and an amphipod scurried away she said, but she wasn't sure if it came out of the bubble. what do i have here?

 

[brandon4291]

Sounds like Valonia Fastigiata, an invasive macro algae that is imported into the reef on LR and other surfaces. It does not seed the aquarium from airborne spores like other assorted algae, it has to be imported in whole or fragment form to regrow. My tanks had them and then they left, kind of like the dinoflagellate/microalgae cycling of a new tank.

Mine were usually dark green, if yours are indeed black then it could be smear algae housing gas bubbles, either a sulfide or oxygen respiration capture. Prob valonia though, no big deal if you'll pick them off before they take over.

Good luck Bro

B

 

[Anonymous]

Daniel,
That's Valonia all right. I remember it being on one of those rocks, although there were only about 10 bubbles or so. They never really spread. You may want to remove that rock, if possible, to manually remove the algae. I believe mithrax crabs will eat Valonia as well.
HTH, Matt