180 litres (~45 US gallons) isn't a huge amount of space. So you will want to think very carefully about what you stock. Many of the Malawian cichlids tend to become hyperdominant in small aquaria, and you can easily end up with one bullying male, a bunch of constantly breeding females, some battered (or dead) males, and untold numbers of hybrid fry. This isn't what you want at all.
To be honest, except for
Labidochromis, I'd reject the idea of Malawian cichlids altogether. They're difficult to do well, and even the "dwarf" mbuna tend to be on the aggressive side. For your first tank, this isn't what you want to deal with.
Tanganyikans are generally easier to maintain in terms of aggression, with the exception of
Tropheus which are pretty nasty. But there are plenty of
Lamprologus and
Neolamprologus species around the 8-10 cm mark that would work well in this sort of aquarium. They don't need excessively hard water, so a combination of inert rocks, silica sand and hard water plants such as
Anubias and
Vallisneria can be used to create a nice aquascape. If you have calcareous limestone, you could use that too, but I find the bright white appearance less attractive than, say, either pink or silver granites. If you have hard water already, you won't need to do much else, but adding a bag of crushed coral to the canister filter, or else adding Rift Valley salt mix to buckets of water, will provide a good insurance policy against pH changes.
Also remember Africa is a bigger place than just the Rift Valley lakes. There are some superb riverine cichlids from the Congo region available.
Steatocranus tinanti is a beautiful rheophillic species that would do well in a tank this size. It is quite widely sold at the moment for some reason, so shouldn't be hard to obtain. It isn't excessively territorial so a couple of males and four females could be easily maintained in 180 litres. They'd be great companions for six Congo tetras and a few dwarf
Synodontis. West Africa has some great cichlids too, with species of
Pelvicachromis being especially nice. Kribs are well known, but other species, like
Pelvicachromis taeniatus are widely available if you make an effort to find them. Again, these would mix well with some African tetras or barbs, as well as the smaller and less aggressive
Ctenopoma and
Polypterus.
Cheers, Neale
Just got my new tank, Regency 80-180 litres, so Ive decided to try something new and start an african cichlid tank. I have no fish in it at the moment, just stacked ocean rock I am waiting for my PH to buff up a little bit. So I am looking for any suggestions as to which fish to get.. ?
Any suggestions or recommendations please.. ???
But if you're looking for a challenge then give them a try. 
