I recently have had several requests for information regarding successfully mixing African cichlids with Central Americans. Rather than responding privately, I'll just post my method so everyone can see.
There are several ways that you can set up a succesful tank. I'll describe the two easiest scenarios for you, and you can choose which way you want to go with.
Scenario one...this looks better, but works the bestr if you can get a harem ( 1 male to 4+ females--up to 7 or 8 mbuna) of a single mild tempered, Malawi species. Labidochromis Caeruleus ( Electric Yellow Lab) or Pseudotropheus Acei are ideal for this. What you do, is put a large pile of rockwork (with lots of caves) on one end of the tank...you can use sections of PVC pipe hidden behind/under the rocks to make the caves. You then put a large piece of driftwood at the other end of the tank, with an open space of at least a foot in between. The mbuna will claim the rocks, and the CA will quickly learn that he'll be out-maneuvered over them...so he'll claim the driftwood area. The open space is important, so if in doubt, go larger than a foot. Don't be afraid to pile the rocks up as high as you want, as long as it's stable. Look at the pictures of Malawi tanks on you-tube and the profiles, and recreate that look in about 1/3 of the tank. This technique almost always works, if done correctly (I've actually never had it fail, and I've set up dozens of tanks this way).
Scenario two... this doesn't look as good, but works very well too. In this case, just spread a few caves (I try to put one for each mbuna, plus a couple more) throughout the tank. Don't pile any rock work up, you just one open space with caves spread about. Then select a few milder tempered mbuna of any species/sex. They will spread throughout the aquarium. The CA will be dominant and will keep the mbuna from fighting too much, but he won't be able to keep them all in their caves. He'll try at first, but will get tired of chasing the fast moving mbuna. The lack of rock work allows the CA to keep the upper hand. This scenario is a little trickier because you do need to avoid the most aggressive species of mbuna (they will eventually challenge your CA, and a 55g just isn't enough room for them anyway)...so do some research to know what to look for. In general, most mbuna with ANY body stripes (horizontal or vertical) may be too aggressive. Fish with a solid body color will be more likely to work out. Don't worry about the fin color, just the body stripes. Also, don't put more than 3 or 4 mbuna in the tank.
These are just two methods that work.
There are several ways that you can set up a succesful tank. I'll describe the two easiest scenarios for you, and you can choose which way you want to go with.
Scenario one...this looks better, but works the bestr if you can get a harem ( 1 male to 4+ females--up to 7 or 8 mbuna) of a single mild tempered, Malawi species. Labidochromis Caeruleus ( Electric Yellow Lab) or Pseudotropheus Acei are ideal for this. What you do, is put a large pile of rockwork (with lots of caves) on one end of the tank...you can use sections of PVC pipe hidden behind/under the rocks to make the caves. You then put a large piece of driftwood at the other end of the tank, with an open space of at least a foot in between. The mbuna will claim the rocks, and the CA will quickly learn that he'll be out-maneuvered over them...so he'll claim the driftwood area. The open space is important, so if in doubt, go larger than a foot. Don't be afraid to pile the rocks up as high as you want, as long as it's stable. Look at the pictures of Malawi tanks on you-tube and the profiles, and recreate that look in about 1/3 of the tank. This technique almost always works, if done correctly (I've actually never had it fail, and I've set up dozens of tanks this way).
Scenario two... this doesn't look as good, but works very well too. In this case, just spread a few caves (I try to put one for each mbuna, plus a couple more) throughout the tank. Don't pile any rock work up, you just one open space with caves spread about. Then select a few milder tempered mbuna of any species/sex. They will spread throughout the aquarium. The CA will be dominant and will keep the mbuna from fighting too much, but he won't be able to keep them all in their caves. He'll try at first, but will get tired of chasing the fast moving mbuna. The lack of rock work allows the CA to keep the upper hand. This scenario is a little trickier because you do need to avoid the most aggressive species of mbuna (they will eventually challenge your CA, and a 55g just isn't enough room for them anyway)...so do some research to know what to look for. In general, most mbuna with ANY body stripes (horizontal or vertical) may be too aggressive. Fish with a solid body color will be more likely to work out. Don't worry about the fin color, just the body stripes. Also, don't put more than 3 or 4 mbuna in the tank.
These are just two methods that work.