it is actually impossible to tell unless on of them gets pregnant sorry just wait and see

depends on the species, some african cichlids you can tell based on coloration like arautus.

Others like frontosas the males will have a big head.

That depends on the type of African Cichlids you have. Take a look at the below website. It should help you determine what kind you have. It will be easier to answer from there.

in many varieties of african cichlids, males will usually lose their juvinile barring patterns or they may fade. Also some female species become very dark when breeding or ready to breed

We need to know what type of cichlids you have before any one can help you.If you don’t know try looking at these web sites and see if you can find out.Please update this post with the names if you know them or a description of your fish if you can’t figure out what they are.

if there are any little yellow orange or red spots on their anal fins they are male.

but not all african cihlids are sexed that way.

As the others have already stated it all depends on which species of african cichlids you have.

With some species, both males and females are near identical (for example, acei, demasoni, yellow labs, calvus, etc), while in other species the genders have completely different color patterns and gender determination is obvious (auratus, kenyi, peacock cichlids, msobo, etc). With these they all start out looking the same and the males undergo color transformation as they mature.

Need more info about your fish.