Pasimoni

The striped pike 'characin', Boulengerella lateristriga, is a ctenoluciid from the rio Negro basin and parts of the upper Río Orinoco. It appears limited to black water rivers and tributaries, where the water is stained darkly with humic acids and the pH can be as low as 3.0 or 4.0. A thin dark stripe from the rear of the eye to the caudal peduncle and dark crossbars on the caudal-fin lobes separate it from the similar B. maculata. It grows to 258 mm SL.

Goulding's piranha, Serrasalmus gouldingi, is a deep-bodied piranha from the rio Negro drainage in Brazil and the Casiquiare system in Venezuela. It occasionally appears in the ornamental trade, sometimes as 'blue tiger piranha'. The eye is bluish or coppery, the body carries vertically-elongate dark spots and the caudal-fin has a blackish basal band. Its native rivers are acidic, mineral-poor blackwater, and it is best kept alone.

Laetacara fulvipinnis is a cichlid from the Orinoco, the Casiquiare and the upper and middle rio Negro in Venezuela and Brazil. Known in the hobby as L. sp. 'orangeflossen' before it was described, it takes its name from the reddish-yellow anal and caudal fins. It has been collected among leaf litter and submerged vegetation in very shallow, soft, acidic blackwater, and grows to around 74 mm SL. A biparental substrate-spawner, it lays its eggs on a solid surface such as a plant leaf.