HELP??? I dont know what it is and its spreading??

Does anybody know what these little things are. They are spreading all over my tank and it seems to kill any type of soft coral that it touches. They seem to be only in shaded areas of the tank but there are a few in the open but you can only see them with the lights off. Also should i try and kill them, if so how.I have tried aptasia x and it seems to work then in a few days it seems like they double.

 

Do they crawl or swim or do they just spread out and overrun everything?

I can't really tell what they are. Do you have a picture of another sample?

 

I have not seen them crawl or move in any way becides opening and closing. It is really hard to get a good picture they are mostly in the back of the tank or between rocks where it is hard to get the camara to focus. If I find some that are out in the open I will try and get a better pic.

 

They are brown in the center with clear tenicals and they have almost white balls on the end of the tenicals.

 

I cant make anything out from the pictures
but the text makes them sound like Hydroids - medussa stages of Jellyfish species

do a google search on Hydroids and see if you get images that match what you have

Steve

 

I dont believe thatthey are hydroids. The only thing that I have found that looks like them are orange ball anemones but instead of orange balls these are white. I have not found any info as whether these are good or bad and how to get rid of them.

 

Go to the bottom of this page. Says they can also be white.
Aquarium Invertebrates

 

Sounds like a species of pseudocorynactis. PSEUDOCORYNACTIS - Google Images

 

Here is a thread from another forum on orange ball anemones. Pseudocorynactis = good or bad? - Reef Builders Forums
Your picture doesn't look like these though. Maybe the picture just isn't great.

 

I believe that is what we have. They are about the size of a dime, and it seems that I need to get rid of them. Do you have any ideas on how to get rid of them. They are really hard to get to.