Horabagrus

Horabagrus

Horabagrus is a small genus of catfishes (order Siluriformes). It comprises two species, H. brachysoma and H. nigricollaris. H. brachysoma is an important food fish, and both species are available as aquarium fish.

Common names

H. brachysoma is known as "Günther's catfish" or "yellow catfish". It is also known as manjakoori in its native range. It is also known by a host of other names, such as "bullseye catfish", "golden red tail catfish", "solar catfish", and "sun catfish". H. nigricollaris is known as the "Black Collared Catfish".

Taxonomy

Horabagrus brachysoma was described by Albert C. L. G. Günther in 1864 under the name Pseudobagrus brachysoma. Horabagrus nigricollaris was described by Pethiyagoda and Kottelat in 1994.

The genus Horabagrus is usually classified under the family Bagridae, but there are disagreements. The genus name is after the Indian zoologist Sunder Lal Hora. Though listed under Bagridae, Horabagrus is not listed under either of the two Bagrid subfamilies by the All Catfish Species Inventory. In Nelson (2006), the genus is provisionally placed in the family Schilbeidae, where it is sometimes recognized as its own subfamily. In de Pinna (1998), this genus is classified as sister to the catfishes Pangasiidae and above, which would require a separate family. This genus has also been classified in its own family "Horabagridae". In a 2007 paper, Horabagrus was not classified under any current catfish families.

Distribution

These two species have a relatively restricted range. They are both restricted to India. H. brachysoma is known only from the Kerala Backwaters, Vembanad Lake and the Uttara Kannada district of Karnataka. H. nigricollaris is only found in the Chalakudy River in Kerala, India. H. brachysoma is found in smooth flowing areas with much vegetation.

Appearance and anatomy

H. brachysoma has a large head and a wide mouth. The eyes are large and can be seen from below the fish. There is a dorsal fin with a hard spine as well as an adipose fin. There are four pairs of barbels, one nasal, one maxillary (sides of the mouth), and two mandibular (chin). H. nigricollaris is sleeker in body shape than H. brachysoma. H. brachysoma reaches about 45 centimetres (18 in). H. nigricollaris reaches about 27 cm (11 in). These two species are quite similar in appearance. H. brachysoma hosts a large black shoulder spot on either side with light outlines. However, in H. nigricollaris the marking extends over the neck, forming a "black collar" (hence the scientific name). H. brachysoma also has a more yellowish body than H. nigricollaris.

Habitat and ecology

H. brachysoma is found in smooth flowing areas with much vegetation. This species occupies lowland areas of rivers and backwaters with mud or sand substrate. It has also been recorded in deep pools and hill streams. H. nigricollaris inhabits hill streams at upper reaches of rivers.

The diet of H. brachysoma has been studied. It is an unspecialized feeder and eats a variety of meaty foods. Food items include crustaceans, molluscs, and fish. Adults may consume terrestrial insects and even frogs. Stomachs of these fish contain detritus which is indicative of its bottom-feeding habits. This flexible diet is beneficial in its variable habitat, in which food availality is affected by monsoons. Feeding rate is known to increase during the breeding season in the months following the monsoon season. Spawning occurs before the monsoons and finishes by the southwest monsoon in the summer.

In the aquarium

H. brachysoma is a common fish in the aquarium trade. H. nigricollaris is more seldomly seen because it is not commercially farmed like the former. Nevertheless, the care for these two species is similar. These fish are said to have a lot of "personality". These fish are adaptable and are not picky about water conditions; also, they are hardy and easy to feed. However, these fish are light-shy and require plants or decorations to hide underneath for darkness; these fish are relatively secretive during the day.

Conservation

Neither species is listed on the IUCN Red List. However, H. brachysoma is considered to be an endangered species and H. nigricollaris is considered a critically endangered species. H. brachysoma is marketed live and supports a local fishery during the rainy season. Overexploitation, habitat alteration, pollution and related anthropogenic pressures on their natural habitats have considerably reduced populations of this species by 60–70% during the last few years. Research is currently being funded to study H. brachysoma, especially its captive breeding. Due to the importance of H. brachysoma as a food and ornamental fish, it embodies the problems that must be resolved for sustainable management, and could be used as a flagship species to provide focus for media attention for conservation.

See also

References

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