how many cichlids in a fish tank?

Hi:

I’m a beginner with african cichlids…..I bought my first 2 fish last week, they are amazing 1- yellow lab & the other I’m not sure, but he’s got brown spot and yellow background with a bit of blue on the top……….. My concern is that I want to add 5 more, but I heared that they are agressive fish, I don’t want that, so which one should I put together with my other 2 fish without having huge fights and blood………………hope this makes sense to you………………………..