Help! Urgent! What is this????

[raebling]

We recently bought this. We were told it was an upside down jellyfish. However everything we have researched, nothing even closely resembles what we have! Also we have only had this in our tank for 3-4 days and we have now lost 2 fish! A black clownfish and a Moorish idol. We watched the Moorish idol swimming around "it" and the next thing we know our beautiful fish starting acting very odd and turned upside down...within seconds! Please help! I really would like to know what this is and if this is what is killing my fish! We have checked all of our levels and everything is fine...nothing else makes sense to what is killing our fish!

 

[Daniel Fishy]

Looks like a bleached rock anemone if it's dying it could release toxins. Run some carbon to absorb any toxins wont hurt.I'm not positive on this maybe someone else can help. Def not a jellyfish!!

 

[MINItron]

That doesn't really look like a Cassiopea, though there are 8 species. In whatever light it sounds like it is releasing nematocysts which can be counteracted by carbon.

 

[Neilfox]

Cycle your tank before you add anything except live rock!

 

[MINItron]

Cycle your tank before you add anything except live rock!

This animal was added to an existing tank, and seems to have cause the death of its tank mates. Anemones don't normally release nematocysts the way Cassiopea can. If it's an anemone it will have a foot under the oral disk that is smaller than the disk. If it is a Cassiopea it will be like an upside down jelly that just stops. There is no foot to hold it in place. It is difficult to find pictures of all of the different species so ID is hard.

If it starts to disintegrate in any way remove it yesterday, and filter with the most carbon and physical filtration you can muster.