What is this?

I found this all over a live rock. Is this harmful for the tank?

 

Zoanthids. Good coral!

 

But it moves around and even sticks in glass some places. That's why I was bit confused if it was apista anemones

 

All I see are zoas. If there's something else in there that's moving around, can you get a better pic?

 

The thing is those are not zoas cos they move around and stick to rocks and all. It does look more like zoas and as far as I know zoas don't move like that. :S

 

Majano anemones

 

+1 on majano anemones

 

So best not to buy from that tank right?

 

Not without some serious eradication:mrgreen:

 

Those do not look anything like a majano to me. Zoas can slowly migrate across surfaces. I have some that do that.

 

I'm going with zoas as well.

 

I've had a ton of Majanos in my tank and they look nothing like those.

 

None of mine looked like those either. But if they move to the glass overnight they aren't zoas. He didn't say how fast they move so I can only guess based on description.

 

Oh they move really fast! Some are even attached to some Algae in the tank and the wave maker. Base is yellowish and slymy like an anemone too.

 

How fast is really fast? You can see some of them in the pic are closed up into a ball. That is what zoas look like closed up. Majano anemones do not have the same look when they retract.

 

I had a majano that did look a zoa when it was closed, but it was clearly a majano. I have to say those look more like zoas than a majano, but it something moves that quickly then I have no idea. Can you get take a short video of them moving so that we can see what you're talking about?

 

Anyways thanks guys for help. Just to be on the safe side I figured not to put those rocks. In case if I had to get rid of them it will be a small problem specially since my tank is a 3x3x3ft cube and reaching bottom is kind of hard lol

 

Mine is 2'x2'x2' and reaching the bottom is still a bitch. I think my next tank will be large but shallow

 

I know it's a stupid thing I did by going for this. Next time I'm definitely going for a 6x3x2

 

If it's moving that fast, I'll put my money on nudibranchs.