Cichlids can only be kept in a dedicated aquarium for cichlids only. You cannot blend South American cichlids with Africans and vice versa. Choose which region you want and stick with that.
They are way to aggressive to be kept with other tropical fish species, even the semi-aggressive fish are too passive and they will be harassed until, they die.
You’ll need to place an algae eater at some point if time if you want to keep your aquarium water crystal clear and if you don’t want to always manually remove algae growth with your hands. You will have algae growth after a while and this is actually a good sign, it means that your tank is fully cycled and it’s own mini supported biotope, so congratulations on having well suited natural aquarium conditions!
When you are considering what type of algae cleaner or bottom feeder, you have to keep in mind that these are the most aggressive fish. You will not be able to have a corydora or algae eater in your tank, your cichlids will consider this their lunch and kill it!
The best advice for algae cleaning and bottom feeding is to get a snail, like an apple snail or a plecostomus. The plecostomus. has a very thick skin and sharp spines and the cichlids will leave him lone to keep your aquarium algae free.
Certain species are much more aggressive then others. for example, the Auratus and Bumblebee are very aggressive while the Electric Yellow Lab is more passive.
You may have conflicts between species is you have a tank full of very aggressive cichlids and then you introduce more passive species. You can keep it under control by heeding the steps to resolving fish conflicts and aggression, but you may not be successful. The only way to know if it will work is to try, but from a budget perspective, it’s best to be aware of the temperament of your cichlids to make sure that you have a good variety of different aggressive levels to keep it fairly even in your aquarium.
You won’t be able to keep other species with cichlids, but once you get to know them better, you won’t want any other fish species. You’ll find them active and entertaining enough! You should never mix the cichlids of different continents together. Keep African Cichlids with Africans and South American Cichlids with the South Americans.
If you are having a hard time choosing between the 2 types, I would suggest the African Cichlids. There is a larger variety available and they are much more colorful then their South American counterparts.