H. compressus is the type species of the genus Hyphessobrycon but is not well-known in the ornamental trade.

Hyphessobrycon was raised by Durbin in Eigenmann (1908) as a subgenus of Hemigrammus, differing from the latter by the absence of scales on the caudal-fin.

Found in both Caribbean and Pacific-slope drainage basins in Central America, from southern Mexico through Belize, Guatemala, Honduras and Nicaragua, and into Costa Rica.

This species clearly shouldn’t ‚ be considered a home aquarium‚ subject at all given its eventual size and the fact it can live for‚ several decades.‚

This species is not recommended to those lacking the facilities to house it for life. Sadly it’s all too often seen for sale as an attractive, silvery 2-3″ juvenile, supposedly suitable for the general freshwater community tank. To make matters worse, it is also usually given an ‘alluring’ name such as ‘black-finned’ or ‘silvertip’ shark catfish. The fate of the majority of these specimens is in all likelihood a depressing one.

While the surface-dwelling form of this species is fairly unremarkable and rarely-seen in the hobby, the blind form is very popular indeed. The two may have diverged as recently as within the last 10,000 years, with the blind form losing its eyes and much of its pigment. This probably happened because the fish needed better development in other sensory areas. Losing unnecessary and energy-consuming aspects of its physiology allowed it to devote more energy to developments such as increased numbers of taste receptors on the head.

This species has been a popular aquarium fish for a considerable period and virtually all fish traded are now raised commercially for the purpose.

It is easily identified by the characteristic bright red or orange underside of the head, which is more pronounced in adults.

Following Miller and Taylor (1984), the genus Thorichthys is identified…

A hugely popular and very adaptable species, the convict is one of the most ubiquitous fish in the hobby. It is often referred to by synonyms such as Cryptoheros nigrofasciatus and Cichlasoma nigrofasciatus. It's difficult to know how much to recommend it to the beginner, as despite its hardiness and ease of breeding, it's not really a community fish. However, if you want to breed a species and witness some amazing parental behaviour, it's an unreserved recommendation. It now exis…

A bright blue variant normally referred to as ‘electric blue Jack Dempsey’ or simply ‘EBJD’ is of unclear origin but it appears to be an ornamental strain fixed from a natural mutation.

Care is as per the natural form although the blue fish tend to remain smaller and some reports suggest them to be less aggressive.

R. octofasciata has a confusing taxono…

Wild swordtails are a fairly basic green colur. However the vast majority of swordtails available in the hobby today are hybrids of X.helleri with X.maculatus or X.variatus. There are a huge number of selectively-bred varieties available, including wagtail, lyretail, tuxedo, albino, neon, red, green and hi-fin.

Swordtails may undergo what appears to be a change in sex. In young fish this may simply be late development. However some adult females develop male characteristics which is thought …