Apistogramma commbrae and other members of the commbrae complex can be distinguished from congeners by the conspicuous double caudal peduncle spot. This species may also be polymorphic, with some males exhibiting red and blue markings on the cheeks and a yellow gular region.

It also exhibits morphological adaptations to an existence among rocks in a flowing environment, such as a cryptic colour pattern, reduced spine length in the dorsal and pectoral fins, ventrally-oriented pectoral fins, slightly emarginate caudal-fin, and reduced body depth.

Reduced fin spines and body depth are typical features associated with the related genus Aspidoras, but the…

The Río Calchaquí rises at almost 6000 m AMSL and flows swiftly through a mountainous valley where it is largely fed by snow melt. The climate is semi-arid and cool with an air temperature of 12-18°C, while rainfall is largely concentrated during summer when the flow can be torrential. The water is hard and rich in salts, with pH measured at 8.04 during the month of August. Aquatic vegetation and filamentous algae grow around the margins and in tributaries.

Despite being a wholly unsuitable aquarium subject, C. idella is often traded as such, with an albino form having been developed specifically for the ornamental market.

Individuals which have outgrown their aquarium or pond should never be released into natural waters, either, since this species has proven capable of causing serious environmental damage under a wide range of climatic conditions.

Occurs naturally in Brazil, Paraguay, Uruguay and Argentina with feral populations in Australia, New Zealand, Ethiopia and Malawi which were purportedly introduced for purposes of mosquito control but are now considered invasive.

Following Lucinda (2008) its natural range comprises the Lagoa dos Patos system, lower rio Uruguai, rio Tramandaí, and rio Mampituba in Rio Grande do Sul st…

The two ponds where H. auca was collected were located on a sand bar deposited by the nearby Paraná river during the Pleistocene.

At time of collection the substrates were composed of sand with submerged vegetation dominated by Egeria najas plus floating Eichhornia in marginal areas.

This species has been traded as ‘six-eyed tetra’ in reference to its colour pattern comprising two dark spots on each flank plus the eye.

Based on the extensive review of the genus by Lucena and Malabarba (2010), in which nine new species were described, P. tegatus can be told apart from congeners by the following combination of characters: lateral line incomplete with 8-13 perforated scales; laterally elongate humera…

A paternal ‘lip brooder’ which has been bred in aquaria.

Post-spawning the male carries the eggs attached to his labial barbels for a period of 12-14 days after which the fry hatch with a large yolk sac attached, this being absorbed over the next 48 hours or so.

During incubation the behaviour of the male i…

This species is not available on a commercial basis but was collected and introduced to the aquarium hobby by Hans Georg-Evers in 2010.

It’s similar in appearance to a number of congeners including C. diphyes, C. erhardti, C. garbei, C. paleatus and C. steindachneri but can be told apart from most of them by possession of two large, indistinct, dark blotches in the middle of each flank.

C. aurofrenatus is currently understood to occur throughout much of the Río Paraguay-Paraná system in Paraguay, and has also been recorded in Argentina and Bolivia.

It was described from Paraguay with type locality given as ‘Aguada near Arroyo Trementina’. The latter is stated to be a tributary of the ‘Rio Aquido Canigi’.