Parguaza

The slate cory, Hoplisoma concolor, long known as Corydoras concolor, is an armoured catfish restricted to parts of the Orinoco river system in western Venezuela. Its uniformly greyish colour pattern sets it apart from congeners, along with a deep body, large eye and relatively long dorsal-fin spine. Mature males develop an extended dorsal fin.

The threespot eartheater, Satanoperca daemon, is a cichlid from the rio Negro, Casiquiare and upper Orinoco systems in Brazil, Venezuela and Colombia. It is mostly observed in acidic, mineral-poor blackwater. Relatively common in the aquarium trade, it is by no means easy to maintain, needing particular attention to space, diet, water quality and chemistry. Two dark blotches on the flank separate it from the similar S. lilith, which has only one.