What is this??? Please help!

[jacobrt]

I have not had good luck with this leather toadstool since I bought it. The polyps are just now starting to come out at all. I am trying to figure out what the yellowish colored hole close to the center is. If it is a mouth that is understandable but it has just become visible. Any help would be greatly appreciated.

 

[mx#28]

It's starting to lose tissue. What are your water parameters and what kind of flow is it in? Anyone in the tank picking at it? How long have you had it? Any other observarations you've made that might shed light on the problem?