Would african cichlids get along well with my pacu?

I wouldn't suggest the mix.Pacus can take pH up to 7.8 so the could live with Malawi Cichlids which there are many hundreds of species. the common Mbunas are neither that fast nor good fighters, as are the Peas.The Pacu will catch and kill them. there are big aggressive Haps in Malawi, Haplochromis livingstoni and Nimbochromis venustus come to mind. They are up to 8-9 inches long so cant be eaten and can live at pH 7.4.