What is this?

[Russellaqua]

My brother-in-law has a FOWLR tank that's been established for 3 years. Recently these two polyps appeared after adding a fish. No coral has ever been kept in his tank. The LFS keeps coral in their fish tanks. Looks kinda like a torch or mushroom to me, but also want to make sure it's not a pest either. Polyps are about the size of a pencil eraser at this time. Here's the pic:

 

[clowns101]

Strawberry anemones,they are kinda a pest IMO.

 

[akabryanhall]

Strange how they showed up after adding a fish..

 

[bct15]

I didn't realize a fish could bring in a hitchhiker, was the water the fish came in added too?

 

[Anthony Calfo]

Don't nuke them just yet, my friend...they may very well be ball corallimorpharians. Much more common as hitchhikers from tropical west Atlantic livestock (hermits, snails, macroalgae...or even from something you bought at a store that has a central filtration system where they mix Florida hermits/snails).

As hard as they are to see by day, you may well have had them for a very long time.

In peak health they often have orange tips, but that is not common at all in aquaria (light and feeding deficiencies). They are usually clear in aquaria.

I had a batch come in on the shells of Astraea snails that I put in one frag tank. I feed so heavy that they flourished and are really lovely.

You will be better able to ID this than sending us images. Take some time checking out references and images on the net. You may or may not have a ball corallimorpharian

ball corallimorph - Google Search

 

[clowns101]

Oh,yup!I think Anthony is right!I didnt even think of Ball anemones since they are so uncommon!

 

[Eternal]

+2 on ball anemone

I have some as well, they came in on a clam. I have not had them bother anything yet and it has been 2 years.

 

[Russellaqua]

Thanks for the responses everyone. I'll forward the info on to my brother-in-law.