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 that are widespread 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 up to and including 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: Chana bleheri, C. cachua, C. orientalis, Candrao. These species are also most suitable for keeping in an aquarium due to their limited size and relatively peaceful nature. Most other species grow to a maximum of 30-90 centimeters. Vijf soorten (A. argus. C. barca, Channa marulius, C. micropeltes and Channa striata) can even grow up to 100 cm and can be considered monster fish that are hardly suitable for keeping in an aquarium.
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.
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 (C. gachau and C. orientalis, C. asiatica, and C. 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.
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:
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 Channa argus and Channa micropeltes, are important consumption 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.
At up to 11 cm, Channa andrao is the smallest species of snakehead. It is also the most peaceful species in the sense that other fish are tolerated as long as they do not fit in its mouth. Males are more brightly colored and larger. Males also grow faster than females.
Channa andro is often marketed under the former names C. sp. ‘Lal Cheng’, C. sp. ‘Assam’, C. sp. ‘blue bleheri’, C. sp. ‘himalayanus’, and C. sp. ‘red’. Also, C. androa is often mistaken for C. bleheri. Channa andrao, however, lacks the front pelvic fin.
The species is endemic to the Brahmaputra River, in northwestern India (Jalpaigur region). There Channa andrao lives in a swamp area near the city of Barobisha. The area is characterized by a continental climate with very hot summers, cool winters and a strong monsoon. The water temperature drops to below 19 degrees Celsius in winter and rises to between 22-28 degrees in summer (preferably keep them lower than this maximum). During the dry winter period, a large part of the habitat dries up. The species then retreats into dug out burrows, in which water remains. Usually such a castle is inhabited by a couple. These observations have given the species the erroneous name of C. amphibieus. Hunting and breeding takes place in the warm summer period, after the fall of abundant monsoon rain.
If they are kept at a higher temperature for too long, (fatal) bacterial infections often occur in the long term. A cool period with a water temperature between 16-19 degrees Celsius is necessary.
Channa andrao can be kept in pairs or in a group. In the latter case, a larger size aquarium is required. Although this species is peaceful, territorial clashes can occur with conspecifics. These are never severe in nature.
An aquarium with densely planted areas, and open swimming areas and sufficient hiding places, and not too bright lighting. 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. Make sure that the temperature of the aquarium is lowered from 15-16 to a maximum of 19-20 degrees Celsius during a season. In the colder period, less food is required and the water level can drop slightly. Young specimen can be kept in a group. After reaching the adult stage, and after forming a couple, mutual aggressiveness will increase. Many hiding places are required when keeping several specimen. With a slightly lower pH value, they show a nicer colour.
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 andrao
This snakehead is a mouthbrooder. Growing with Channa andrao is quite possible. To initiate breeding, the water temperature should be lowered. Putting a male and a female together does not necessarily result in a pair. It is best to form a group, from which a pair can arise. The culture is initiated with a consistently higher water temperature with delayed water changes and maintenance. After mating and spawning, the male collects the fertilized eggs in the mouth. Within 3-5 days (sometimes longer) the eggs hatch. The female produces unfertilized eggs that serve as food for the young. Young that grow up with their parents therefore grow faster than young that were removed from their parents. The brood care lasts 2-3 weeks.
Patrick de Pijper
Bijgewerkt op 12 August 2023 door John