Nhamundá

The lesser bleeding heart tetra, Megalamphodus socolofi, is a characid known only from the rio Negro basin and the rio Nhamundá in Brazil. One of three similar species in the 'bleeding heart' subgroup, it shares their reddish humeral spot, found in no other characid. Generally peaceful, although adult males are territorial to an extent, it mostly inhabits sluggish tributaries, side arms and forest lakes.

Satanoperca lilith is an eartheater cichlid known only from Brazil, where it is widely distributed along the Solimões/Amazon main channel. Despite that extensive range it is uncommon in the ornamental trade, where it is sometimes called 'one-spotted demon fish' or 'one spot eartheater'. A single dark blotch on the flank separates it from the closely similar S. daemon, which has two.