Yes, African butterflyfish can live together. African butterflyfish live better and more healthily when they are with others of their own species. This is especially true if they also have enough swimming space and a varied diet.
Additionally, African butterflyfish can also do well with other small fish that tend to stay in the lower parts of the tank.
However, care should be taken when considering keeping another species of butterflyfish along with your African butterfly, as they may become aggressive around certain species.