Life span of brittle starfish?

[SueAndHerZoo]

Hi Gang.
I noticed my brittle star out and about at lunchtime today (which is highly unusual) and today when I got home from work he/she was still out in the center of the tank. I tried moving her/him back to his favorite spot under a rock cliff and it barely responds to my moving it. I have had this thing since I first got into the hobby - it's probably 14" across when his tentacles are spread out. Could it be dying of old age? Not sure what, if anything, i can do for it but I hate just watching it die.
Thanks in advance.
Sue

 

[gar732]

Not sure how long they live but I had one for about 12 years. It was going strong until I lost it in the move.

 

[SueAndHerZoo]

I've had this guy about 8 years but don't know how old he was when I bought him. Still Googling to see if I can find average lifespan. Nothing has changed in the tank and he's survived so many tank changes and re-aquascapes I can't imagine what's taking him down now.
Sue