Be sure to cycle the tank first. Don't do what I did and needlesly kill your fish because you thought that cycling a tank isn't that improtant.
It's kind of expensive. But for the Africans, especially the Lake Tanganyikans who like their
ph leel above 8.0, it's worth it. Texas holey rock is limestone and naturally raise the
ph to the levels that these fish need without the use of chemical additives. Between that and all of the caves that it gives them to swim and breed in... well you can't really ask for a rock better suited for an African Cichlid tank.
If you are looking to get some, look on ebay. Do a search for Texas Holey Rock. It's some of the best prices that you are going to find without digging it up yourself. (Done that too)