In Brazil P. castexi is currently banned from export, although it can still be legally obtained from other countries. There's a high level of polychromatism (differences in colour and pattern) displayed by this species, and in the hobby some of the colour forms have been given distinguishing names. Below is a list of some of the commoner varieties, along with some defining characteristics:

Otorongo Ray (also known as "Jaguar" Ray, P25, P26, P28 or P35): This popular variant has…

P. orbignyi is one of the species often labelled as "teacup ray" in dealers' tanks. It can be tricky to identify when young, and we have seen it misidentified on numerous occasions. The species it resembles most closely is P. humerosa, although these can be distinguished by examining the skin of the fish. The texture of this is typically rough in P. humerosa and noticeably smooth in P. orbignyi. Provided you're sure what you're buying, it is one of the best species for t…

P. motoro is one of the most popular members of the genus with aquarists. Whilst it is quite easily obtainable and hardy once settled in, it does grow very large so make sure you can house it adequately long term. It should also be noted that the males of this species are among the most violent when in the mood for spawning and females can end up on the wrong end of a serious beating. If you're keeping a pair or group of these keep a close eye on proceedings and be prepared to separate them…

P. leopoldi is aruably one of the most stunning freshwater species in the hobby and comes with a price tag to match. A fully grown one of these makes a jaw-dropping sight. Sadly exports from Brazil are now illegal under the IBAMA regulations, although captive bred fish are available occasionally. The price tends to be even more expensive as a result. A rare form in which the light spots appear as rings with black centres is known as P. leopoldi "eclipse" is more costly still. The stunn…

Julidochromis are commonly known as "Julies" in the hobby. As with other Julies, large water changes should be avoided as this can cause mated pairs to turn on one another.

There is some speculation as to whether this species has been placed in the correct genus. It has a different shape to other Julidochromis, having a pointed snout. It also exhibits different patterning, with blue edging to the dorsal and anal fins, and the horizontal stripes are very dark in colour. Furthermore i…

This lovely dwarf mbuna makes a great choice for newcomers to Mbuna due to its temperament, subdued but unique colouration and the fact it can be kept in smaller tanks. Iodotropheus is the only genus of Mbuna which has a very limited distribution within Lake Malawi, with its three (possibly two; the validity of I. declivitas is disputed by some experts) members being restricted to the south eastern arm of the lake. I. sprengerae is sometimes confused with certain populations of the similar looki…

A real bruiser of a cichlid, H. elongatus is not seen for sale very often, and with good reason. Pound for pound it must rank as one of the most aggressive cichlids available in the hobby. It is such an efficient predator that, in some of its native countries, it is used to control populations of Tilapia. As a result it's definitely not recommended for the inexperienced aquarist.

The common name is derived from the row of 5 dark markings that run laterally along the flanks of the fish. I…

This beautiful species is critically endangered in nature but is not that rare in the hobby being quite easily bred.

Many sources refer to it by the invalid scientific name Astatotilapia latifasciata and may also be seen for sale as Haplochromis sp. "zebra obliquidens" or H. obliquidens. Sadly it's thought that the latter fish has never even been exported and is extinct in nature. Furthermore, H. obliquidens is a Victorian species and does not even inhabit the same lake as H. l…

An exceptionally hardy and adaptable species tolerant of a wide range of physiological variables and flexible of diet, factors which have allowed it to become established as an alien species around the globe. Its high reproductive potential and low vulnerability to predation have made it a cause for concern to conservation scientists although as yet there remains no proof of it exerting a negative effect on native fishes in countries outside its natural range.

This species was originally classified in the genus Limnochromis. There are a couple of colour morphs available and these should not be mixed in aquaria, as they may hybridise.
In nature, this fish feeds in a similar way to Geophagus species, in that it will sift sand through its gills to extract invertebrates hidden in the substrate. It is a deep water fish and has been recorded foraging at depths of up to 200 metres. These movements seem to be related to the presence of the plankton on which…