Hello, I've a 130 gal. tank, and I want buy some Polypterus or Erpetoichtys for it. I've already two Polypterus palmas polli, an Agamyxis pectinforns and a Crenichicla sp. Xingu. So...what can I keep?
This is a common question that's hard to answer. I think it's dependent on your system.
What kind of filtration do you have?
What is the footprint of this 130g?
I would pick the species you like and list them from your most favorite to the ones you just 'like'. Start at the top and add one at a time over several months and see how your system holds up.
With lots of filtration and a minimum of 50% weekly water changes, you poly stocking can be pretty high.
My favourites are dehlezi and teugelsi (unobtainable in my place...sob!); some time ago, on this site, I saw a bichir species with an huge dorsal fin (not a selected variety). MY tank is 120x60; the filter is a 1300 l/h.