Numerous ornamental forms of this species have been selectively line-bred for the aquarium trade, vernacular names for which include "sunset", "sunburst", "double red", "triple red", "gold", "white gold", "orange flash" and "albino". It has also been assigned the 'A' number A200 under the DATZ system with possibly conspecific, related forms similarly numbered A201, A202 and A203 depending on locality.

Th…

This is an exceptionally hardy and adaptable species. It's not an especially common fish in stores, but is quite widely available in hobbyist circles. The common name arises from the row of modified, paired scales that form a keel running from the base of theto the caudal fin….

The eye of Anableps species is split horizontally by a band of epithelial tissue. It has two corneas, two pupils, a single, egg-shaped lens and one retina that's also split into two sections. The lens is oval and asymmetric with the upper part flattened as in the human eye and the lower section curved as in most other fishes. The upper cornea is thicker and enriched with glycogen which possibly helps to protect it from drying and UV irradiation. Two horizontal flaps of the iris are thought …

The genus Acarichthys remains monotypic and was resdescribed by Kullander (1986) who characterised it by the following: lack of epibranchial lobe; comparatively few (12-14)rays; pelvic fins with relatively broad tips (branches of the first ray are equal in length or the inner is slightly longer); possession of a single supraneural plus 14-15 vertebrae (these characters taken as a combination); no caudal extensions to swim bladder; no caudal ribs.

Its current taxonomic position is based largel…

T. heteromorpha was first exported for aquaria in the early 1900s and has gone on to become one of the most familiar, enduring species in the hobby. It has suffered as a result of its popularity to a certain extent with the mass-produced fish we see today lacking much of the colour seen in wild specimens and even exhibiting morphological deformities in some cases.

Several selectively-bred ornamental strains have also…

One of the most ubiquitous species in the hobby and several ornamental strains are available including ‘long-finned’, ‘golden’, ‘albino’, and ‘super red’, for which care is identical to that of the ‘standard’ fish.

Unfortunately the degree of inbreeding amongst farm-bred stock has resulted in a situation whereby many of the fish available today are genetically weak and prone to disease or develop physical deformities.

It was initially going to be described as Hyphessobrycon cardinalis by Myers and Weitzman (1956) but just before this was due to be published Schultz presented an alternative description in the hobbyist magazine ‘Tropical Fish Hobbyist’ and named the fish after the publication’s founder, Dr. Herbert R. Axelrod.

A significant proportion of the fish available in the aquarium trade are still wild caught or derive from community-led breeding projects such as Project Piaba in the middle Negro region, where this sp…

This species is also known by the alternative names ‘green’ or ‘Chinese’ barb. The natural ‘green’ form is an infrequent find in the aquarium trade whereas the selectively-bred ‘golden’ variant is farmed in huge numbers and is among the most popular of freshwater aquarium fish.

The latter was first produced in the 1960s and is now so ubiquitous that many hobbyists are initially unaware that it is not the natural form.

An easily kept cichlid whose character more than compensates for its somewhat drab colouration, S. casuarius is sometimes seen for sale as "Humphead", "Lionhead" or "Buffalohead" cichlid. It is a reophilic fish meaning it inhabits fast waters. Its swimbladder is modified to reduce buoyancy and thus prevent it from being swept away by the strong currents in it's natural habitat. In the aquarium it spends most of it's time resting on the substrate or hiding …

Vieja bifasciata are often confused for vieja synspilum but can be told apart as bifasciata have two prominent horizontal lines running between their eyes (hence the name). They are a very colourful fish and respond to their owner's presence – usually looking for food!

Bifasciata are not particularly demanding in terms of water parameters and easy to keep, especially if suitable tankmates can be found. It is sometimes the case that a pair of fish that will not live together in a tank on …