Chaca (genus)
Encyclopedia
Chaca is the only genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 in the catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

 family Chacidae. These fish are commonly known as squarehead catfishes, frogmouth catfishes, or angler catfishes. These unusual fish have a sedentary lifestyle and spend much of their time immobile.

The name Chaca is derived from the fact that when removed from the water, they will rapidly repeat the sound "chaca". Only C. chaca makes these sounds; the other species do not.

Distribution and habitat

Chaca species are found in freshwater
Fresh Water
Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...

 from eastern India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 to Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....

. C. chaca is found in the Ganges
Ganges River
The Ganges or Ganga, , is a trans-boundary river of India and Bangladesh. The river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India into Bangladesh, where it empties into the Bay of Bengal. By discharge it...

-Brahmaputra River
Brahmaputra River
The Brahmaputra , also called Tsangpo-Brahmaputra, is a trans-boundary river and one of the major rivers of Asia. It is the only Indian river that is attributed the masculine gender and thus referred to as a in Indo-Aryan languages and languages with Indo-Aryan influence...

 system of India and the Ayeyarwady River
Ayeyarwady River
The Irrawaddy River or Ayeyarwady River is a river that flows from north to south through Burma . It is the country's largest river and most important commercial waterway. Originating from the confluence of the N'mai and Mali rivers, it flows relatively straight North-South before emptying through...

 of Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....

. C. bankanensis originates from the Sundaland
Sundaland
Sundaland is a biogeographical region of Southeastern Asia which encompasses the areas of the Asian continental shelf that was exposed during the last ice age. It included the Malay Peninsula on the Asian mainland, as well as the large islands of Borneo, Java, and Sumatra and their surrounding...

 region. C. burmensis is found in the Sittang River
Sittang River
The Sittaung is a river in south central Myanmar in Bago Division. The Pegu Range separates its basin from that of the Irrawaddy. The river originates at the edge of the Shan Plateau southeast of Mandalay, and flows southward to the Gulf of Martaban...

 in Myanmar and possibly the Ayeyarwady drainage.

C. chaca is found in rivers, canals, and ponds of grassland, scrubland, deciduous forest, and rainforest habitats. On the other hand, C. bankanensis is only found in the rainforest, where it inhabits peat.

Appearance and anatomy

Chaca catfish have an elongated, broad, and flattened head. The mouth is terminal and very wide. There are three or four pairs of barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...

, though if the nasal barbels are present they are minute. These fish grow to a length of about 20 centimetres (7.9 in).

The dorsal fin is short and possesses strong, serrated, fin spines, which are strong enough to inflict wounds.

Ecology

These fish live in soft substrates where they will bury themselves as camouflage, both for protection and to feed. These fish are ambush predators. They feed on prey such as small fish, including cyprinid
Cyprinid
The family Cyprinidae, from the Ancient Greek kyprînos , consists of the carps, the true minnows, and their relatives . Commonly called the carp family or the minnow family, its members are also known as cyprinids...

s and pupfish
Pupfish
Pupfish are a group of small killifish belonging to ten genera of the family Cyprinodontidae of ray-finned fish. All pupfish are especially noted for being found in extreme and isolated situations, in various parts of North America, South America, and the Caribbean region...

es. They will lie in wait, well camouflaged, in preparation for prey to swim by. Sometimes, they use their maxillary barbels (attached to the upper jaw) to lure prey fish closer to its mouth, similar to a worm jerking in the water, although this behavior is contested by some aquarists who do not observe this behavior. When the catfish is ready to strike, the Chaca will open its large mouth rapidly, creating a vacuum that pulls in water and its prey, which may be up to half the fish's own length. These fish are also able to use this large mouth as a means of propulsion; when frightened, they will gulp a large amount of water and expel it through their gills.

In the aquarium

Chaca species are occasionally available as aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 fish. These fish are nocturnal and are usually inactive. A bizarre phenomenon is shown in that Chaca appear to lower the pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

of the water, and so maintenance of water chemistry is necessary. These fish have been bred in captivity.
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