THINK OF SOUTH American fishes and we mostly think of species from the Amazon basin. Like all river basins, the Amazon has an edge, in this case, one of those edges is the Guiana Shield, a region rich in fish and habitats and a major contributor to the species available in the aquarium hobby. Rising just north of the mouth of the mighty Amazon River and containing a sliver of northern Brazil, the easternmost edge of Colombia, all of Guyana, French Guiana, and Suriname, and all of south and eastern Venezuela, the Guiana Shield is an ancient geological formation which developed at least 1.7 billion years ago. It is an elevated plateau, a raised slab of rock over which flows tropical forests, dry savannahs, rolling hills, steep valleys, and the…
