Dead Toadstool

does it have sufficient water flow? it needs it

 

Plenty of flow, I think it was tired of being stung from the brain.

 

Mine had just been closed up for a few weeks maybe around a month and I just started to run some carbon and it opened up ... Try runninging some carbon if you don't already and see if that helps. Other than that I wouldn't worry to much about it right now.

 

I run carbon. The toadstool just looks shriveled up and ugly.

 

The possible reason that the Toadstool is not expanding its polyps, is because of the fact that it is sloughing(molting), hence the shedding skin.
Increased water flow will help to remove algae and detritus from accumulating on the head of the Toadstool and allow the Toadstool to remain expanded. My Toadstool has not shed in over a year, since I changed and increased the water flow to it. Toadstools are dimorphic, meaning they have two types of polyps(Autozoids and syphonozoids). Autozoids are used for food capture and protection, whereas the smaller polyps are used for water circulation between the polpys and head of the coral.
Unfortunately, syphonozoids will not alleviate the problem of detritus and other irritants from accumulating so increased water flow is important, as is their natural process of shedding.
The illustration you are showing us is a common sight for Toadstools, as I have seen this in my own Toadstool as well as those in pet shops. Shedding, water flow or possible chemical warfare and other conditions can bring about this unhappiness or natures way to clea itself!