What's this

[Reef Shrimp]

It appeared spontaneously, there was no such thing

 

[*GAREEF*]

Looks like a baby bubble tip anemone to me.

 

[Gumbies R Us]

Anemone! Did you recently buy coral frags, or do you have an anemone besides that one in your tank?

 

[Mr. Mojo Rising]

There's also a huge aptaisia there....

 

[Reef Shrimp]

Anemone! Did you recently buy coral frags, or do you have an anemone besides that one in your tank?

I didn't buy any anemone.