1 african knife fish with others fine in a 75g?

[poly-nomial]

with 4 other relatively small polys?

 

[benzjamin13]

It'll be fine. If you're talking about X. Nigri and Sens and/or Dels, you're good.

 

[jschall]

Yeah my 4" X. nigri is great with my sens and del which are up to 7.5", so I'd imagine an 8" one would be good with up to 20" bichirs at least.