Xingu has a black-water waterfall and for some reason the fish found in Rio Xingu are 10 times more colourful than their counterparts in the surrounding areas. This fish is so unique it doesn't occur anywhere else on earth!

30 - 40 species of fish with vibrant forms of colour live exclusively in the Xingu. Some of the most loved fish come from there, including the clown pleco.

https://www.redbubble.com/shop/ap/35448436?ref=studio-promote

http://encycloquaria.com/fish/more/Potamotrygonidae/Potamotrygon/

there's 100 variations on some species of fish. sorting catfish is hard there's 100 species in the hobby, and 2000 l-number catfish. that's fish yet to be sorted into proper taxonomical structure.