Amount of Dwarf Cichlids

Depends on type of dwarf, sex ratio, and landscaping. Multiple male rams would have no problem splitting up a 55g. Multiple male apistos could be kept, but you would need LOTS of structure, and some kind of "line of sight" divider around mid-tank. They would also need to be added at the same time. Most apistos will form harems, and since female territories are not as large you could probably do a male and 3-4 females in a 55g. Individual species, and even individual male aggresion levels vary widely. Best bet would be to get males of different species and put them in BEFORE they are sexually mature so that they can iron things out without too much actual physical confrontation. You could also erect a temporary divider so that the males could each claim half the tank. Once territories are firmly established (about a week) the divider can be removed removed.

Ohh, you said dwarf cichlids. Most dwarfs come from south america, although a few Tanganyikan species are also considered dwarfs (shelldwellers) as are a few West African Species commonly known as kribs. The cichlids in the Assorted African Tank are not dwarfs and will all reach sizes of 5 inches at least. The idea behind the overcrowding is that the more dominant fish cannot "lock on" to any one fish and cause serious damage. This should be accompanied by LOTS of rocks (rocks stacked all the way to the top if possible). This allows all fish plenty of cover, and will actually result in them spending more time away from shelter (the fact that they know there is plenty of cover at hand makes them more bold.) This type of tank should also have extra filtration because of the high bioload, and recieve very frequent water changes. Someone else will have to help with number of fish and species selection (not all africans can go together). I would suggest passing on the mixed Africans unless you are an expert on species identification as these tanks sometimes include hybrids of unknown teperament. A mixed African tank gone wrong ends in a big tank with one dominant fish and all others being slowly beat to death.

From what I understand, the first two will work together since they are both very aggresive, the Yellow lab will not since it is traditionally refered to as the mildest of the mbuna (it will get its butt kicked).

You can mix lakes IF you are very careful to take diet and behavior into account, but it's really not recomended unless you have years of experience working with rift lake cichlids. IMO there's really no reason to, but I'm a bit of a biotope purist when it comes to tanks.

You definately can't mix rift lake cichlids and SA since thier water chem requirements are on opposite ends of the spectrum. Central American cichlid's water chem is a little closer to what the rift lake cichlids need, but again, I wouldn't do it. Mixing different species of cichlids is hard enough under the best circumstances, and mixing ones from different continents is well.......not reccomended. You will end up with a bunch of nice looking fish, on the verge of killing each other, and displaying none of their natural behaviors. There's nothing like having an accurately set up biotope tank to bring out the best in your cichlids.

Good Luck.

a lake tang tank ou could put a bunch of shell dwellers in there and have a big society, it would be pretty sweet. But! Apisto is the way to go IMO