Is my sea urchin dead?

[Michel]

A few days ago my urchin just stopped moving. He just sits in one corner without any changes in the tank.
Yesterday he started losing his spines and now he lost all his spines on one side of his body.
I thought maybe he had air in his mouth or something so I tried laying him on his back so if he had air in his mouth it could escape.
But after about an hour on his back he now got covered in little nassarius snails.
It's kinda strange because he still got half his body covered in spines, but nassarius snails only cover him when his dead I guess?

In the picture there are about 5 on him, but right now there are already more then 10.

Would he still be somehow alive or is he dead and should I take him out?

Its only a 10g nano (skimmerless) so I better take it out when its dead, but I dont wanna take out an animal thats still alive

 

[MS38]

Yes, and I am speaking from experience, the urchin is 100% dead. Sorry...

 

[Michel]

I'm afraid you are right . I have put him in a little container clipped in the top corner of the tank so he can't pollute the tank when he turns out to be dead.

I think I also might have found the problem. Two days ago I put in a small piece of Poly-filter in the back chamber to see if it would change color.

The right one is new (as reference) and the left one is the one I put in two days ago. It looks like it starts changing a bit pink/red which indicates iron... I think I need to figure out where this is comming from...:mad: