Okay the shell dwellers seem to be gaining some popularity now so here is one:
Scientific Name: Neolamprologus multifasciatus
Common Name: Multies
General background: These fish are found in Lake Tanganyika among the leftover shells from snails that live in the lake. They generally live in shallower areas of the lake. The males breed with multiple females with in their territory.
Aggression level: Not very aggressive but have no problem trying to hold their own or keep other out of their territories, in my experience.
Tank Set-up: A 10gal tank should be fine for shell dwellers, though 20 gal make awesome shell dweller tanks. I have seen some nice 10gal setups with small breeding colonies of multies. Sand with a lot of shells is best. These fish love to make home out of shells and during breeding these shells are very useful. Shells are also a great hiding area.
pH Range: ~8.0 I have kept mine in 7.8 and they have done fine.
Temp: ~78 degrees F, many keep their tanks at 80 degrees F. I keep all of my tanks in the 76-78 range depending on depth found and have had no issues.
Feeding: A protein diet should be fine. NLS pellets (or other similar pellets), shrimp pellets, brine shrimp or flakes should be fine. I feed mine shrimp pellets and NLS pellets and they do fine.
Breeding: Generally these guys should not be to hard to breed. If you provide enough females per male (5 or so females per male) and have a lot of shells and good water quality they should breed for you. The males will breed with multiple females. The fry will hide in your shells and swim out on occasion. If you want to separate fry, I suggest picking things that you can pull out of the tank easily and can dump or transport to a fry tank - you will never catch them all they are fast and don't travel far from their hiding spots (its a real pain!).
Maybe not the best pic but the only one I got on the computer atm. One of my smaller ones: