C. caudimaculatus may be confused with the congener C. similis but can be told apart by possession of a well-defined, blackish spot on the caudal peduncle vs. a ‘smudged’ bluish marking.

C. guapore also has a comparable colour pattern but possesses a distinctly rounded snout and tends to swim above the substrate.

Wild populations vary in colour pattern depending on origin, and some populations have previously been described as distinct species.

A form from Peru has a particularly silvery body colour, for example, while another, marketed as ‘super red’ possesses an unusually long red stripe on the body, extending much of the length of the dark central stripe. A population from around Boa Vista in the rio Branco system, Pará state, Brazil has an ocellus o…

This is the type species of the genus Aequidens and has the widest distribution of any member species. It exists in various colour forms depending on locality with variants from Ecuador and Peru being particularly sought after since they develop striking red (Ecuador) or orange (Peru) colouration on the lower part of the jaw, head and anterior portion of the belly whereas those from Brazil tend to have an overall grey/blue/green colouration, for example.

Despite its type status it's long…

The majority of records pertain to the rio Guaporé (Río Iténez in Bolivia), the main affluent of the rio Mamoré, which drains the vast tropical wetland known as the Pantanal, and the upper rio Paraguai, which also has its headwaters in the Pantanal but flows in the opposite direction. The Guaporé and Paraguai are connected due to rising water levels during the annual wet season.

This species has been a ubiquitous aquarium fish since its discovery, and is produced on a commercial basis in several countries, therefore wild fish are no longer collected. An ornamental albino form is sometimes available.

Apart from its distinctive colour pattern, it can be identified from related species via the following combination of charac…

This species is very common in the aquarium trade and is also referred to as ‘jewel’, ‘red minor’, ‘blood’, or ‘callistus’ tetra.

A number of selectively-bred ornamental strains have been developed, including ‘metallic’, ‘long-finned’, ‘balloon’ and ‘fairy-fin’.

Characiformes is among the most diverse orders of freshwa…

It exhibits slightly different behaviour to the majority of congeners in that it tends to swim in midwater and spends a large proportion of its time away from the substrate. Its morphology exhibits corresponding adaptations towards a pelagic existence with a relatively large eye, a more terminal mouth position, more strongly-forked caudal-fin, and more symmetrical body shape than most other Corydoras species.

The original type locality is ‘Rio Guaporé, Brazil’, supposedly in the vicinity of Pontes e Lacerda in Mato Grosso state. However, this was modified by Nijssen and Isbrücker (1980) to ‘Brazil-Goias, Rio Tocantins, road between Pedro-Afonso (08°59’S 48°12’W) and Itacajá (08°18’S 47°45’W)’. This is confusing since the distance between these two localities is well over 1000 km, although it appears that the former is correct as per our image of specimens with locality details.

L. taeniata is the largest-growing and second most widely-distributed member of the genus although it’s a rarely-seen in the aquarium trade.

It can be distinguished from all congeners since it uniquely possesses 5 lateral scale rows between the lateral line and dorsal-fin origin (vs. 4 or 6–8 in the remaining species).