How many African Cichlids for a 40 gallon Tank?
How many fish in a 40 gallon tank? You've probably seen many articles on this subject and several different formulas to exact an equation but if you look closely you'll see that they all produce very similar numbers. With that being said I would think you'll be safe using any of the popular methods.
While you're researching the different varieties of Cichlids make sure you do a compatibility check for any plants and other natural décor you want to decorate with. One thing I know for sure is Texas Holey Rock is completely safe for any Cichlid fish.
Whichever one you use to calculate the population in your tank take keep in mind, the amount of plants, rocks and substrates take their own space and need to be factored into your equation. With the very small fish that aren't the aggressive type you can lean to the higher number without adverse affects on the health of your fish. With the larger fish you'll want to lean towards the lower side because as they get bigger, they get wider and taller. Then there are those species who give off more waste than the average fish. That needs to be considered to prevent a fully stocked tank from ending up being dirty all the time because of the more than normal waste.
If you decide on keeping only Dwarf Cichlids with a 40 gallon Aquarium you can keep 10 to 12 at one time. For the medium size varieties 3 to 4 will do nicely. Those classified as large have a maximum capacity of 4 if you don't have a overload of decor and 3 if you do.