It's a Papyrocranus, probably P. afer as they are most common (they are usually called Reticulated or Marbled Knifefish but are really variable in colour and pattern). Does this place have no signage? Most of your ID photos are of very common home-aquarium species.
@Chlidonias Signage was strange here, in the ‘main’ section, it wasn’t awful, most species were signed and as such I took photos of the signs to identify the species I saw. However, in the freshwater section and upstairs the signage was pretty poor - some species were signed but there were lots that were not (think of it like the signage at a sea life centre perhaps if you have been to one before)
All in all though there were some very nice species here, I assume the commoner species were more of a ‘tank filler’ maybe? Thank you for the ID