There are in excess of 30 described species of Serrasalmus many of which appear superficially similar and have confusing taxonomic histories. S. rhombeus is among the most convoluted of all with numerous synonyms of which S. niger is the most well-known. There has also been a muddle surrounding the common names "white" and "black" piranha, both of which have been used to describe the species.

Of greater interest to both scientists and hobbyists has been the discovery of n…

There are only two described species in the genus Sandelia. Both have limited natural ranges in parts of South Africa, which in itself is odd as they're completely isolated from other genera of anabantoids. This is probably due to some ancient radiation of species, but as yet remains unresolved. Sandelia spp. are also considered the most primitive of anabantids, as they possess a less well-developed labyrinth organ than their relatives.

S. capensis is of considerable conservation importa…

One of the smallest species in the genus, it is rarely seen in the trade. A pity, as its diminutive size makes for an ideal aquarium subject.

Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as the labyrinth organ. So-called due to its maze-like structure, this organ allows the fish to breathe atmospheric air to a certain extent. It is formed by a modification of the first gill arch, and consists of many highly vascularised, folded flaps of sk…

There are currently 20 species of Ctenopoma, most of which most are seldom seen in the aquatic trade. Originally the genus was significantly larger, but a number of original members were reclassified by Norris in 1995. Whilst describing what were apparently two new Ctenopoma, he discovered sufficient morphological anomalies in the fish to erect a new genus for them. The name Microctenopoma was chosen, although this does not relate to the size of the fish. Similar defining characteristics were al…

Numerous ornamental forms of this species have been selectively-bred for the aquarium trade, some of which include. It has also been assigned the 'A' number A234 under the DATZ system with possibly conspecific, related forms similarly numbered A235, A236, A237, A238, A239, A240, A241 and A242 depending on locality.

The genus Apistogramma is among the most speciose of South American cichlid genera with around 70 species valid at present but many more awaiting description. In addition …

M. fasciolatum is found in clear water with lots of surface and overhanging vegetation in nature.

This species can be exceptionally long-lived and there are reports of specimens surviving in aquaria for over 30 years. It is named after the explorer Mary Kingsley, and often goes by the common name of Kingsley's climbing perch. While Ctenopoma are closely related to the Asian climbing perch (Anabas sp.), they are not known to have the ability to cross areas of land like this species.

Like others in the suborder Anabantoidei, the species possesses an accessory breathing organ known as t…

An ideal species for the newcomer to 'oddballs'. It is exceptionally hardy, long-lived (it can survive for over 15 years when cared for properly) and exhibits some interesting behaviour. It appears to have evolved convergently with leaf fish of the genera Polycentrus and Monocirrhus (they're not closely related). All these species mimic leaves and other aquatic debris to assist them in hunting their prey. If you add live food to its tank, you will see the typical stalking behaviou…

This species isn't especially popular in the aquarium trade but is undoubtedly interesting despite its lack of colour. In addition to its survival ability in the absence of water it's also capable of producing audible sounds though the purpose of these has not been fully-studied. Naturally-occurring xanthic and albino forms have also been recorded.

There is considerable confusion as to the taxonomic status of the two species currently occupying this genus, with ichthyologists widely…

This fish is spawned very infrequently in captivity but some reports have been made. Fish are sexually mature from 4" and a pair should be obtained by growing on a group of youngsters and allowing a pair to form naturally. Once this occurs the other fish will most likely be eliminated so it is wise to be vigilant in order to avoid uneccessary losses.

Apparently courtship occurs in an open section of water surrounded by floating plant material. The courtship consists of the fish circling …