Like all polypterids, Rope Fish (Erpetoichthys calabaricus) are strictly carnivorous and prefer 'meaty' foods. Mine get a varied diet of frozen bloodworms (their favorite), small pieces of 'krill' or shrimp, small pieces of frozen silversides, Hikari Sinking Carnivore Pellets, appropriately-sized live earthworms, occasional live 'ghost shrimp' and occasional pieces of frozen beef heart. They will also eagerly consume any fish that they can catch and swallow but I won't feed mine live fish because of the risk of introducing diseases and/or parasites.
-Joe