Like many cichlids, members of the genus Herichthys share something of a confused taxonomic past. Erected in 1854 with H. cyanoguttatus the type species, its members were moved into Cichlasoma by Regan in 1905. However following a review of Cichlasoma by Kullander in 1983 it was once again deemed valid. In 1996 Kullander suggested Herichthys should only contain species "sharing a colour pattern of short vertical bars or black spots posteriorly from the middle of the side, and a unique breed…

Recorded throughout much of the Amazon basin, with its range extending eastwards from the Ucayali system in Peru as far as the Tocantins drainage which flows into the Atlantic alongside the Amazon at its delta. The southern extremity of its range appears to be the Río Mamoré in Bolivia, a tributary of the rio Guaporé, and the northern limit the Essequibo basin, Guyana.

An attractive but not often seen species in the hobby. This is quite odd considering how common it is in many of its native habitats, where it is known as sardina. It has very strong pectoral muscles, and uses these to jump from the water to catch flying insects or to escape potential predators. It can make leaps of several metres in length….

The common name of this species is derived from the Portugese dourado and refers to the beautiful golden colour of the fish. We've included this species on the site purely because there have been an alarming number of juvenile fish showing up in some aquatic stores and, as a result, in hobbyists tanks. This species is simply not suited to captive life in any respect. If you see one for sale, and they are undeniably an attractive fish, please don't be tempted to buy it.

As responsib…

This is the smallest of three similar-looking species most commonly-referred to as the ‘bleeding heart’ subgroup, the other two being H. erythrostigma and H. socolofi.

All possess a reddish humeral spot which is not present in any other characid with other shared characters including possession of 6 -14 maxillary teeth, 7-9 scales above the lateral line, 5-7 scales below the lateral line and 26-33 anal fin rays.

This species is available on a relatively regular basis, although it’s sometimes confused with the similar-looking congeners H. loretoensis and H. metae.

It can be identified via the following combination of characters as per Géry (1977): elongate in shape with body depth fitting 3.8-3.9 times in its standard length; caudal peduncle narrow, its depth fitting 1.8 times in its length; head short, interorbital broad, snout short and rounded; dorsal-fin insertion an…

The Brycon genus is large, at present containing over 50 species. A number of these are very similar, a couple of which (B. rubricauda and B. orbignyanus) resemble B. cephalus quite closely. However this one is the most common in nature and is likely to be the species seen on sale most often.

Commonly known as the matrinxã in Brazil, it has an interesting life cycle, migrating twice per year over large distances according to the season. The first movement occurs at the start of…

An infrequently seen but very interesting oddball species for those who are looking for something a little different. To others, it might appear to be a rather nasty species. In the wild, it swims in voracious feeding groups. Apparently, it can home in on weakened or distressed fish as it has a very well developed sense of smell. Other specialisations include the tiny eyes and particularly slimy skin. The former are reduced in size and covered by a thin layer of skin so they are less likely to b…

Lungfish are among the most intriguing of "oddball" aquarium subjects, being able to survive in the most extreme conditions. They are very ancient fish, having remained virtually unchanged for millions of years. Unlike its African relatives, N. forsteri cannot survive in completely dry conditions for long, although it does require access to atmospheric air to survive. It possesses only a single lung (the African species have paired lungs), which is formed via a modification of the swim…

This species has been introduced into many areas in Africa for commercial purposes, and it's had a hugely detrimental effect on local fish populations in some of these environments. The most notable case is that of Lake Victoria, where much of the endemic cichlid population has been wiped out. L. niloticus is thought to have directly contributed to the extinction of over 200 endemic species in the lake by predation, or outcompeting them for food. The IUCN have included it in their list of t…