I will say one thing though regarding that tank. As strange as the stocking was the fish all looked chilled and healthy. They'd obviously got used to the immense volume of footfall in the airport too.
It would been interesting to see what the softness/hardness of the water was given the stocking, or does it really matter that much when we are told that fish adapt over time? Would running the tank neutral, in the goldilocks zone as it were, really harm the soft water lovers or hard water lovers?
I must admit though it did look strange having plecos and parrots in with African cichlids!
If this surprises you, then you would hate some of the aquariums displayed around here. I can think of three off the top of my head that have the exact same stocking; it's quite common. Yes, I know there is a rule about mixing SA cichlids with Africans, but honestly, if it works, it works. Plecos...well, they can pretty much go with anything, lol.