Tropheus

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Tropheus

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Cichlidae
Genus:	Tropheus

Tropheus is a small genus of six species of cichlid fish endemic to Lake Tanganyika in East Africa. The genus Tropheus is widespread across all regions of lake Tanganyika, from Burundi in the North to Zambia in the South.Males and females are relatively similar but do display obvious sexual dimorphism. Males attain a somewhat larger size. All species maternally mouthbrood their eggs and fry and it is this characteristic that provides their latin name. Tropheus comes from the Greek "trophos" which means "to nurture". The genus is fished lightly by the local population but has never become a staple food fish due to its relatively small size and its habitat which enables it to dart between rocks when threatened.

Most species occur along the coastal fringes of the lake at depths of less than 3 metres. These rocky shores, with numerous rocky outcroppings and boulder formations form a habitat similar to many of the mbuna cichlids of Lake Malawi. This habitat provides shelter and, due to the shallow depth and the long hours of strong sunlight, heavy algal growth on which the Tropheus feed. The only tropheus species to dwell further out and deeper in the lake is Tropheus Duboisi which in general inhabits deeper regions of the lake down to around 15-20 metres. All species are algal grazers and have underslung mouths adapted to rasping algae and microinvertebrates from submerged rocks.

The genus is popular with aquarium hobbyists due to the beautiful markings and interesting behaviour of the fish.

1 Classification
- 1.1 Variants and Distribution
2 In the Aquarium
3 Images of Tropheus
4 References

[edit] Classification

Six species of Tropheus are currently recognised:^[1]

Tropheus annectens Boulenger, 1900
Tropheus brichardi Nelissen & Thys van den Audenaerde, 1975
Tropheus duboisi Marlier, 1959
Tropheus moorii Boulenger, 1898
Tropheus moorii kasabae Nelissen, 1977
Tropheus polli Axelrod, 1977

[edit] Variants and Distribution

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Because of the vast scale of Lake Tanganyika, species have parallel evolved in distinct breeding colonies, some only a matter of a few hundred yards apart. As a result of this there are a bewildering number of colour variants of each species. The most notable example is among Tropheus moorii which alone has over 100 recognised and named colour variants^{[citation needed]}. The best way to consider the distribution of species variants is to split Lake Tanganyika into its 4 main geographical zones which roughly equate to the northern, eastern, southern and western shores^{[citation needed]}. These zones and some well documented variants from each are:

Burundi (North)
- mboko, bemba, kiriza, caramba.
Tanzania (East)
- maswa, bulu point, ikola, kipili.
Zambia (South)
- kiku, mbita, nangu, kasanga.
Congo/Zaire (West)
- chipimbi, kipampa, kachese, kongole.

[edit] In the Aquarium

Tropheus species have been popular in the aquarium trade for nearly a century. The fish have, however gained something of a reputation for fragility and are regarded by many cichlid keeping aquarists to be rather demanding to keep. It is certainly true that they should not be considered beginner fish but neither should they be unfairly derided as, when kept in appropriate conditions they make superb aquarium fish.

[edit] Aquarium Set-Up

Tropheus are best kept in species tanks in groups from 15 and up. With smaler groups the dominant fish will hunt down the weak, resulting in a higher risk of wounded and death animals trough fights. In larger groups the agression of the dominant fish is spreaded over the whole group resulting in less problems. They are not suitable community tank fish because their unique requirements will not be met in a mixed set-up and because their innate aggression. Some individuals are more aggressive than others and this is influenced by factors related to the aquarium such as volume and mix of individuals. For these reasons a 400 litre aquarium should be considered the minimum volume.

The aquarium should be set up with piles of flat rocks (slate is a good choice) built up to form crevices and caves for the fish to withdraw into and to help split the tank up and provide territorial boundaries. Fine gravel is suitable, however coral sand or marble acts as a pH buffer increasing the alkalinity and hardness of the water in the aquarium. As Tropheus occur in the surge zone in the wild, the water in the aquarium should be well oxygenated. The aquarium should be well filtered, and small volumes of water should be changed frequently. The water chemistry and temperature should match their natural habitat in Lake Tanganyika, water temperature in Lake Tanganyika is relatively stable and this should again be mirrored in aquaria.

[edit] Feeding

Tropheus are algae grazers and in the wild will only consume minute quantities of animal food (ie: micro-organisms taken in with the algae whilst grazing). They cannot deal with high protein foods due to having an extremely short digestive tract^{[citation needed]}. As a result, the majority of commercially available fish foods are unsuitable for them as they are derived from fish rather than vegetable matter. However, this does not mean that these fish are hard to feed, far from it. There are several superb vegetable flakes that are available in all shops based on spirulina and other vegetable matters. They will also do very well on fresh vegetable matters such as romaine lettuce and spinach. The general consensus on feeding is as with all types of tropical fish - it is far better to feed small amounts throughout the day than to give one big feed^{[citation needed]}.

[edit] Diseases

Tropheus are susceptible to the same sorts of viral, bacterial and stress-related diseases as other fish but should not prove delicate as long as the above issues with water quality, feeding, group size and aquarium volume are addressed. They are however known to be particularly prone to a condition called "bloat" which can be very hard to deal with. Bloat is purported to be caused from a range of organisms which include the flagellate (Cryptobia sp.) and/or numerous bacterial species that cause intestinal problems in the genus. Affected fishes discharge white feces, may sway or have swim-bladder problems and frequently stop eating. As with every aspect of fishkeeping prevention is beter than cure.