I read in a post on another site that they dont survive very well in captivity. From what the post said they will slowly die from starvation. I believe the post said they may last about a year. I wanted to get one at one time and after reading that changed my mind. Others that have them may chime in here also but thats about all I have to offer.
"You must feed it daily with phytoplankton, Marine Snow or any other "filter feeding" foods that are available out there. I've had mine for about 4 months now."
I found that at another site I regularly visit. There were people that said they had theirs anywhere between 3 months and 2 years. They all said regular target feeding was one of the keys to keeping them alive.
Good luck and post some pics if you get one. Hope that helps