hi
just thought I'd add that frontosa's are tanganyikan cichlids
requiring much higher ph than your other tankmates (8.6 ideally)
they will not be happy fish otherwise....display dark colour and sulk in the corner etc...
in the wild they prey on julidichromis spec. or anything they can fit in their mouth but will take most pellet food in the tank.
your fire eel likes much sorfter water so they aren't suitable tankmates (imho)