Identify?

[kloudie]

I've seen these spring up on a zoa frag I got, was wondering what they might be ?

 

[mcintosh]

Those are hydra. It is a cnidarian (like corals) that have a free swimming "jelly" stage and then attach to the rock. They are like mini Aptasia in that they have a terrific sting and are fairly prolific, but they stay small and if you cut down on the feeding many times they will die out. They can be pests, however.

 

[Sammibaz]

For what it's worth...I have these too but they are only behind a rock where NO ONE can get, nor can my scrapper get there! They were introduced to my tank on a small zoa frag a long while back. They spread like crazy. I knew what they were and what a punch they pack to other corals...but I didn't know how to get rid of them. I spent hours taking rocks and corals out, picking the hydroids off with tweezers and putting back into the tank. I had to stop the maddness...it was consuming me. I realized I couldn't do anything about it (easily) so I 'let it go'. I added a few fish and inverts as part of my rebuild. These little hydroids started disappearing!!! I don't know exactly 'who' is eating them, but I would suspect it is either my Coral Banded Shrimp, my mandrin pair or my pair of Melanarus Wrasse.

 

[kloudie]

I did recently have a peppermint shrimp pass away so that might explain why I have just noticed them. I have dealt with aptatia before, I'm just going to clear them out before they spread more. Easy enough on my 10 gal to pull rock out and scrape it off.