Unini

The false adolfoi, Brachyrhamdia rambarrani, is a heptapterid catfish from the Rio Unini, a blackwater tributary of the lower rio Negro in Brazil. It occurs with, and mimics, Hoplisoma davidsandsi, sharing its basic colour pattern, while the common name comes from its resemblance to H. adolfoi. Rarely seen in the trade, it tends to turn up as a contaminant among shipments of other species.

Burgess' cory, Hoplisoma burgessi, long known as Corydoras burgessi, is an armoured catfish apparently endemic to the upper rio Negro basin in Brazil. One of several similarly patterned congeners, including H. adolfoi, H. davidsandsi and H. duplicareum, it has a black marking restricted to the area beneath the dorsal fin and extending into it, with a yellowish patch on top of the head. Rio Negro habitats are mostly blackwater tributaries and flooded forest.

Sand's cory, Hoplisoma davidsandsi, long known as Corydoras davidsandsi, is an armoured catfish apparently endemic to the rio Unini system in the lower rio Negro basin, Brazil. One of a group of rio Negro species with an oblique dark bar along the back, it shares with H. melini a bar that splits in two above the caudal peduncle. It has a pale orange area between the facial stripe and dorsal bar and no further dark markings on the flanks.