Channa gachua – Brown Dwarf Snakehead

Channa in general

Channa, commonly known as Snakeheads, are primitive predatory fish and members of the family Channidae. They are a group of perciform (perch-like) fishes whose affinities are unknown, although recent studies on the molecular phylogeny of bony fishes consider snakeheads as most closely related to the labyrinth fishes (anabantoids) and the synbranchiform eels, which include the spiny eels.

The Channa family includes 31 species widely distributed in Asia from southeastern Iran and eastern Afghanistan eastward through Pakistan, India, southern Nepal, Bangladesh, Myanmar, Thailand, Laos, Malaysia, Sumatra, Indonesia, Vietnam, Korea, and China to and with part of Siberia. In addition, 3 species of the related Parachanna family are found locally in parts of Africa.

The Channa varieties have large differences in size. The unofficial term Dwarf Snakehead was coined by aquarists to refer to a group of Channa species that do not grow larger than 25 cm: Channa bleheri, Channa cachua, Channa orientalis, Channa andrao. These species are also most suitable for keeping in an aquarium due to their limited size and relatively peaceful character. Most other species grow to a maximum of 30-90 centimeters. Five species (Channa argus, Channa barca, Channa marulius, Channa micropeltes and Channa striata) can even reach 100 centimeters or larger and can be considered monster fish that are hardly suitable for keeping in an aquarium.

Origin

Fossiles dated from 50 million years ago indicate an origin in the southern Himalayas (India and East Pakistan). From 15 million years ago, the animals have spread by the expanding intertropical climate zone to parts of Europe, Africa, and larger parts of Asia.

Physical features

Channa have an elongated body and are distinguished by their long dorsal fins large mouths full of teeth. They earn their common name Snakehead because of their flattened shape and the scales on their heads that are reminiscent of the large epidermal scales on snakes.

Channa have gills to breathe water like most other fish. However, subadults and adults can also breathe air to supplement their demand for oxygen. Snakeheads are in fact obligatory air breathers and must have air from the surface otherwise they will drown. Unlike many other airbreathing fishes, Channa have a series of cavities in the rear section of their head. These suprabranchial chambers are filled with folded tissues that have a high surface area, and allow oxygen change to occur directly between air and their blood. Unlike mammals, they lack a diaphragm and use water to exchange old air with fresh air each time they take a breath. Thus, their ability to breathe air when out of the water is limited. They appear to breathe air more frequently when swimming actively.

The genera Parachanna (native to parts of Africa) is described apart from the genera Channa because of a more primitive implementation of the airbreathing section.

Snakeheads are known to migrate over short distances overland to find other water basins, using the ability to breathe air. When moving over land they curve their body in an S shape first, before launching themselves forward by a powerful stretch. In high humidity conditions, Channa are able to survive from 2 up to 4 days out of the water. When placed in direct sunlight, however, they desiccate and perish in minutes to several hours. In contrary to what is believed, Snakeheads are not known to leave the water for any reason other than making their way back to the water after flooding. The only snakeheads that actively leave the water belong to the dwarf species (Channa gachau, Channa orientalis, Channa asiatica, and Channa amphibius). Even then there is a clear reason for leaving the water, such as escaping overpopulation.

Snakeheads can be found in a wide variety of waters and water conditions. They are found in tropical, subtropical and temperate regions. Snakehead fish are not dependent on the oxygen level in the water. Many (not all) species can also tolerate widely varying temperatures and water parameters for a period of time. However, they are very vulnerable to sudden changes in water parameters.

Behavior

Snakehead fish are predatory fish that feed on plankton, insects and snails as youngsters. As they grow larger, the larger species switch to a menu consisting mainly of fish, frogs, crabs, shrimps, small aquatic mammals and waterfowl. Young specimens usually hunt in groups. When they reach sexual maturity, they isolate themselves to lead a solitary life or live in pairs. They then develop a higher degree of aggression towards conspecifics and often also towards other fish. Often a couple will not tolerate other fish in the limited space of an aquarium.

Snakeheads are not active swimmers. In addition to hunting, they actively move only to draw air from the surface. Usually, they swim in the middle water layer or rest on the bottom to strike from an ambush. A number of species, however, are pelagic and are more active swimmers. All snakeheads are capable of launching themselves forward from a standstill by briefly curving their muscular body and stretching it forcefully.

Brood care is an important behavioral trait for Snakeheads. All species violently guard and defend their eggs and young. The majority of species lay eggs that rise to the surface and are guarded there. A number of smaller species collect these eggs and store them in a burrow that may or may not have been dug. A number of species are mouthbrooders.

The snakehead is a popular – eccentric – fish among a specialist group of aquarium keepers. Snakeheads are elegant, powerful, alert, and calm fish, with a willful character. The mutual communication, hunting technique and brood care is fascinating. Some aquarium keepers specialize in keeping the largest species and have a pet-like experience. Some rare and variegated species (such as Channa barca) are among the most valuable aquarium fish on the market.

Snakeheads often have changing patterns and colors as they grow. With the exception of the dwarf species, the young of most species are much more beautifully marked and colored than the aging fish. With age, they usually get a duller ground color. Some aquarium keepers lose interest in them as they grow. It is therefore wise to do some research before purchasing.

As predators, snakeheads are by nature not a suitable choice for the average community aquarium. They are intolerant and usually soon the only fish. A special aquarium is required for keeping snakeheads. Aquarium keepers have different experiences when it comes to mixing snakeheads with other tankmates. Most species are best kept alone. Combining snakeheads with territorial or aggressive tankmates is not recommended. An intimidated snakehead hides, tries to escape, and refuses to eat. The extent to which other fish are tolerated in the small habitat of an aquarium depends very much on the species, but within that probably also on the individual specimen and the specific situation. There are a number of general experiences per group:

Dwarf species

Due to their small size and relatively mild temperament, most dwarf species pair well with robust, fast fish of a similar size. Provided these fish are not too territorial or aggressive. It should be taken into account that most dwarf snakeheads live in their natural environment in an eco climate zone with seasonal extremes in water temperature and water values. As a result, they cannot be kept at a tropical temperature all year round. A temperature reduction for at least one season per year is necessary to keep them healthy. Co-residents must also be able to cope with this.

Medium sized species

This group contains the most diversity in terms of behavior. Many of the larger species (between 30-60 cm) can be combined with relatively fast and robust fish of a similar size, for example, large cyprinids. General experience is that combining with other fish species works best when the snakehead fish are not yet too big and when the other fish have already settled. Newly introduced fish are often killed immediately. It varies greatly by species and experience. Often the tolerance to other fish is temporary. When a pair of snakeheads is formed, the co-inhabitants (also conspecifics) are usually chased and killed.

Large species (60 – 130 cm)

These snakeheads themselves require an amount of space that most private aquariums are unlikely to be able to provide. Extremely large private aquariums are usually just big enough to hold one fish or a couple. In general, the same applies as with the medium varieties. Fish that grow with them from an early age are often tolerated. Newly introduced fellow residents are often killed immediately.

A number of large species, such as C. argus and C. micropeltes, are important food fish. They are considered highly invasive and destructive to the local ecosystem outside their natural habitat (see also the documentary Invasion of the Snakeheads). After the fish were sighted in several places in the US, import bans and a ban on owning a live specimen are in effect in most states within the US.

Channa gachua – Brown Dwarf Snakehead

With a maximum length of 18-36 cm, the Brown Dwarf Snakehead is one of the smaller and most peaceful species. The body is usually brown to blue-grey, with blue fins, with a red border. There are many regional variations with spots and dots.

Channa gachua has a very large distribution area that runs from Iran and Afghanistan to Vietnam (Iraq, Pakistan, Nepal, Afghanistan, India, Bangladesh, Bhutan, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia, Indonesia, China, Singapore, and Sri Lanka ). De soort is dan ook het meest in de handel beschikbaar.

The distribution area of Channa gachua extends over both tropical and subtropical areas. Partly because of this, the color variations and the maximum size vary greatly (from max. 18 to max. 36 cm). Due to the many regional differences, Channa gachua is no longer considered by modern ichthyologists as a single species, but as a complex of closely related species. It is likely that the current species classification will be differentiated in the future. Recent specializations concern Channa andrao and Channa harcourtbutleri.

The fish from a tropical area require a constant water temperature. The fish from a subtropical climate can tolerate extremes of 14 to 36 degrees Celsius, but not continuous tropical values. Before purchasing, first determine where they come from, in order to be able to take care of it properly. In the natural habitat, other water parameters vary widely. They survive in water with varying pH values from 3.1 to 9.6. However, all varieties do very well in water with a pH between 6 and 7. What Channa gachua (like other snakehead fish) cannot tolerate is sudden changes in water values, especially the pH value.

Often Channa orientalis is confused with Channa gachua. Channa gachua and Channa orientalis occur side by side in Sri Lanka. However, Channa orientalis is endemic to Sri Lanka and is distinguished by the lack of the lower fins.

Channa gachua has a peaceful temperament for a snakehead, although there also appear to be regional differences in terms of tolerance. The species generally can be kept well in a group of conspecifics. However, if a pair forms, the aggression increases. The species also keeps well with other fish species, provided they are not too aggressive and cannot be mistaken for food.

There are large mutual variations in color and color patterns. The difference between male and female is barely noticeable. The most reliable way to sex the animals is to wait until a couple forms from a group.

The aquarium

An aquarium with densely planted areas, open swimming areas, and sufficient hiding places. Some darker spots are appreciated. Make sure that it is possible for them to get air from the surface, otherwise, they will suffocate. Close the aquarium tightly. They manage to escape from the aquarium through the smallest hole.

Specimens that come from a cooler habitat require a period of lower water temperature. However, this temperature does not have to be as low as with Channa bleheri. A temperature of 18-21 degrees Celsius in winter and 22-25 degrees in summer is sufficient.

Diet

Carnivore. All common small meaty foods are eaten, such as red mosquito larvae, krill, large brine shrimp, freshwater shrimp, insects, posthorn snails and especially earthworms. Pieces of fish are hardly eaten. They also accept frozen food and often also dry food.

Breeding Channa gachua – Brown Dwarf Snakehead

Has often succeeded in captivity. For more info, read this breeding report.

Breeders should be aware of regional differences. Careless mixing of fish from different areas can inadvertently lead to hybrids

Video

Author

Patrick de Pijper

Copyright images

Channa gachua TH203 – W004 by Acapella – Chan gachu 120715 0262 krw by Wibowo Djatmiko – CC BY-SA 3.0
Hung Jou Chen
AquariumGlaser.com