Where should I buy my Tanganyikan shell dwelling cichlids? Where should I get the sand for the substrate?

I would suggest you visit all or your local pet shops and find one that specializes in aquariums and hopefully knows a thing or two about the little guys you want. If no store seems to carry a lot of cichlids, just ask questions about special orders and start buying a few items of supplies from that store... get to know them and let them get to know you. Build a relationship with a particular store and then use them for your special orders. That will insure you get to see the fish before buying and that they will try to get quality fish for you at a fair price.

MM

aquabid.com

There are a few breeders there that auction fish and can safely ship them to you. Good luck.