How many African Cichlids can I fit comfortably in a 55 gallon?

A 55gal has a lot of prospects for african cichlids set up, but i err you on the least aggressive side if you like the yellow labs the most.

In a 55gal about 5 yellow labs, 5 acei's and 5 rusty's would be sweet..

The cylindricus are tanganyika's and have very big teeth, johannis are very aggressive as well as the red zebra's.

If your looking for an aggressive tank i would go with zebra's and kenyi's.

But there are a lot of possibilities to achieve an mbuna setup, more so is what you will like, google mbuna setups, there you will get a wealth of info..

My advice is to start reading. I haven't done much for africans, but I do know that setting them up can be a challenge. Look at tanks that experienced people have run to see what works, and then read about the fish, and figure out why it works. Picking up some books on the topic couldn't hurt either. Depending on the water where you live, you may need to do a bit of reading on chemistry for buffering the CaCO3 to get a higher pH. Dietary needs, plant compatibility, temperature and everything else is a little different than the usual, "plop some flake in to a cycled tank at 25C with dechlorinated tap water changes some times." A couple weeks of study and asking questions will save you a lot of time and money.

You are going to want groups of 4-5 4f/1m or 3f/1m of each. In a 55g you will want to choose mildly aggressive species like rustys or labs something along those lines....red zebras maybe but kwnyis will get a little too rowdy IME. You are going to want heavy filtration and be ready for weekly water changes. If you stock accordingly to aggression/color etc. you can probably do 4-5 groups of 4-5 fish. 15-20 fish.