Xiao;4687258; said:Chinatown supermarkets are your best bet. Sometimes they sell elvers as well.
Be warned, it can some serious searching to find one in good condition sometimes though. Alot of times I go in the markets I see them in some dreadful physical condition. I've seen stores that have them displayed, but had their mouths crushed or broken off I assume to prevent getting bit while handling them.
Also be sure to check what kind of water they're being kept in. I initially had mine in complete fresh, but didn't adjust well right away. I added a little marine salt and it has been fine ever since.