If you are concerned about feeding the only fish that I suggested that wont eat most prepared fish foods is the eel. Mine only eats live foods. I dont know about the goldfish but you should keep the ph around 7.0. Here are some better pics.
Polypteus delhezi:
Polypterus endlicheri:
Indo dat:
African knife:
and I could keep all those in the same tank? two of each except the knife?
mm... do they swim around at all?