Zbfish source?

[Yiing Lin]

Greetings to all,

We are just starting work with zebrafish, and I was wondering if anyone 
knows of any reliable source from which we may obtain fish of a certain 
age and sexed.  

We've gotten some fish from local pet shops, but trying to distinguish 
their genders is very difficult.  I'm not sure if it's because the shops 
just have one gender or if it's really that difficult at first to sort them.

Thanks!

						-Yiing Lin
						 ylin at acpub.duke.edu