Aripuanã

The Amazon puffer, Colomesus asellus, is a freshwater puffer found throughout much of the Amazon basin, with records north to Guyana and Venezuela. Also traded as the South American puffer or 'SAP', it is told from congeners by a transverse row of dermal flaps across the chin. It lives mostly in well-oxygenated river habitats, is intolerant of organic waste, and forms loose aggregations, so a group of 6 or more is best, away from the general community.

Gastrodermus gracilis, long known as Corydoras gracilis, is a small armoured catfish from the central Amazon basin in Brazil, known from the rio Juriti in Pará to the rio Juma in Amazonas. Sometimes called 'shy cory' in the hobby, it has a lightish body with a dark arched stripe along the upper flank, a pattern shared with Brochis arcuata, C. narcissus and Hoplisoma urucu. Only in G. gracilis does the stripe end at the base of the upper caudal-fin rays. It apparently favours minor tributaries with dense riparian vegetation and acidic, tannin-stained water.

Iguanodectes geisleri is a characin from the rios Madeira and Negro in Brazil and the upper Río Orinoco in Venezuela. Traded with the similar-looking I. adujai as the 'red line lizard tetra', it differs in having a black lateral stripe beneath the red stripe and 20 to 25 anal-fin rays (28 to 34 in I. adujai). Adult males carry red markings in the pectoral, pelvic, anal and caudal fins.

Leporinus brunneus is an anostomid from the rios Madeira and Negro in Brazil, the Orinoco in Venezuela and Colombia, and the Casiquiare canal. The largest officially recorded specimen measured 256 mm, and an aquarium with base dimensions of at least 210 by 60 cm is needed.

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.

Synaptolaemus latofasciatus is a headstander from the upper Orinoco, the Casiquiare Canal and the middle-to-lower Amazon in Venezuela and Brazil. Described from a single specimen and placed in Leporinus until 2011, it was then recognised as the fish described as Synaptolaemus cingulatus. Alternating transverse bands of orange or yellow and dark brown or black run along the entire body, and snout shape and colour pattern vary with locality.

Iguanodectes variatus is a characin from Brazil, recorded from the Guaporé, Madeira, Branco, Trombetas and Urubu river systems in the Amazon basin. It belongs to a small genus of elongate fishes in the family Iguanodectidae and grows to around 103 mm SL.