Parnaiba basin

Apistogramma agassizii is a dwarf cichlid found through much of the Amazon/Solimões basin, from the Río Ucayali in Peru to the Capim River in Brazil. Colour and pattern vary considerably with locality, and numerous ornamental forms have been selectively bred for the trade. It inhabits slower-moving tributaries and creeks where leaf litter collects. Captive-raised fish suit the community aquarium, while wild fish are best kept alone or with small dither fishes.

Geophagus parnaibae is a comparatively small cichlid endemic to the rio Parnaíba drainage in Piauí and Maranhão, northeastern Brazil. Only described in 2006, it has been in the hobby since at least 1988, traded as G. sp. 'Parnaíba'. The undescribed G. sp. 'Pindaré' is sometimes labelled with the Parnaíba name but is totally distinct. Maroon and whitish horizontal bands in the caudal fin help identify it.