Can a African cichlids fish live in salt water?

Most African cichlids are from the Rift Lakes in the Great Rift Valley, and they require very specific water chemistry. Although their water contains some salt (sodium chloride) it also contains other salts of potassium, sodium, calcium and magnesium. Rather than being salt water, it is very hard water.

So to answer the question - no, African cichlids can't live in the kind of salt water that is used in marine aquariums. However, most of them (with a few exceptions, such as the hardy kribensis) can't live in true freshwater either. They need water that matches the chemistry of the Rift Lakes, which is unlike any other body of water on Earth.