It is generally not advisable to mix neo-tropic cichlid species in the same tank. I know the kribs are Central African, but they count in this.
With the kribs, the Congo Tetra are very good, but a larger group. This is a species that is always more impressive with 10 or more, and a ratio of male/female something like 5-6 males and 5 or 4 females. They do however need a 4-foot (120 cm) length tank; don't know the dimensions here.