Jellyfish ID?

[StrangeDejavu]

So I was looking in my fuge a minute ago and pushed down some of my ulva sea lettuce that was floating on the water surface. I see this thing fly out of the macro and swim down to the rock. Got the turkey baster out and sucked him up into a cup. Is this a medusa stage hydroid? None of the pics I come across on Google match what I see. It's very small, could fit on a pencil eraser. I'm pretty confused how I could have ended up with it since I started with 100% dry marco rock. The macro algae was my only form of "seeding" this tank with live stuff. I picked through it profusely, trying to only let copepods and amphipods in but removing flatworms and anything else I could see. That was 2 months ago and this is the first time i've seen this thing in my tank.

<iframe width="420" height="315" src="https://www.youtube.com/embed/a0ePKZqTIL4" frameborder="0" allowfullscreen></iframe>

 

[cloak]

Is this a medusa stage hydroid?

I believe so.

http://www.lionfishlair.com/hitchhiker.shtml

http://www.wetwebmedia.com/jellyidfaqs.htm

 

[StrangeDejavu]

Just removed two smaller ones out of the fuge, and saw one on the glass in the DT. Went to suck him out but he disappeared when I was reaching for the baster. Should I be worried about these guys? Or will they come and go as the tank matures?

 

[StrangeDejavu]

Should I be worried about these guys? Or will they come and go as the tank matures?

 

[Dkuhlmann]

What did you find out about them when you Googled it? I think it's a pretty cool creature but ya it has to go.

 

[CStrickland]

They're no big deal. It's really common in new tanks, similar to how a lot of people see a pod explosion but the it levels off on its own. I'm not sure whether it's because their food source stabilizes or what, but as your tank balances out you'll notice them gone one day.
It's only an issue for reefers who are trying to raise fry, nothing else even notices the sting, and if a fish tries to eat it they just spit it out with no issue.

They are pretty awesome to see while they last tho, nice pics too.

 

[StrangeDejavu]

Agreed, they are very neat to watch. When I Googled, I found some threads here and on other forums where people had them completely choking out rocks. They would pop up in a zoa colony and sting them, which would lead to death in the zoas. One guy had to take out all his rock and boil them just to kill them. Freaked me out when I read that, but i'm hearing from different people that it's part of the aging process, they'll come and go. I hope so!

Edit: So apparently there are different types. Colonial hydroids are the ones I mentioned above, where people boiled rock and tore down tanks. Apparently there are also digitate hydroids. Not sure which I have. Just going to keep up on water changes and hope they go away.

 

[CStrickland]

Yeah. Colonial hydroids can be bad news, they are attached to rocks and kinda resemble a tube worm or polyp coral. These aren't that