The snakeheads (lat. Channidae) are members of freshwater ray-finned fishes family from an Anabantiforme order. The fish got its name due to the similarity of its scales and head shape with a snake one. There are two genuses known, which exist nowadays, and one extinct genus. The species are encountered in equatorial Africa (Parachanna genus) and South, South-East, East Asia (Channa genus); some kinds of Channa genus were introduced into North America.
Initially, the genus, which the snakeheads were considered to belong to, was called Ophicephalus, later the scientists divided it into two independent genuses:
The 1st one is Channa and it includes Asian species. Nowadays, it has 36 fish kinds in it.
The 2nd one is Parachanna and it has only three snakeheads kinds which inhabit in Africa.
Apart from the fish species which have a scientific name and description, there are several geographical fish morphs and some new kinds of the fish species that currently have an undefined status.
The name of the genus “Channa” originated from the Latin “channe”, which is a generalized name used for the ocean perch species.
Habitat in the wild
In the wild the species can be encountered in various areas: from South-West India and West Afghanistan to East China, in some parts of Siberia in the Far East, in the island of Java in the South, from White Nile to Senegal and Chad River in the West, and Kongo River in Africa.
Nowadays, some species are introduced into the waters of North America, where they rather quickly invade more and more new territories (source).
Though the fish kind is a rather widespread one, we know very little about the habitats and their populations size in the wild. As a rule, their habitats are in boggy areas of rivers and lakes, paddy-fields, channels, etc.
In the wild they are quite often found in rather dirty, overgrown with vegetation and sometimes in almost dried up water basins, where it seems nothing could live at all.
The fish digs into the wet bottom and this way it can survive even a short period when the water basin dries up. But more often than not it doesn’t come to this.
Due to the fact that species can travel short distances over the flat muddy land, they just move to some other waters with better living conditions. They do this by pushing off with their tail and rowing with their fins.
In some countries large species are used as food fish. The fish flesh is not fat, but it’s rather coarse.
However, the fish grows fast and its species are rather undemanding, which ensures snakehead successful breeding in artificial ponds, while feeding the fish with frogs and their larvae. At that, some other fish kinds just won’t survive in this conditions.
The main distinctive feature of all snakeheads is an elongated fusiform body flattened a bit closer to the fish tail. The fish dorsal and anal fin are well-developed, they have soft rays. Both fins go along the fish body till its tail-stem. The fish fluke is large and round shaped, while its pectoral fins are small and rounded.
They have large head, which is a bit flattened on top and almost all of it is covered with scales. Its jaws have many small setaceous teeth that grow in several rows.
The fish eyes are not large; gill slits are very large. The fish lateral line goes along its lateral center line, but a bit higher and it becomes curved on the fish forebody.
When the atmospheric temperature is about 10—15°C and the humidity level is high, headsnakes can stay out of water for two or even three days. This ability helps them to travel from one water basin to another over the dry land.
One of the impressive features of snakeheads is their ability to survive at low oxygen content. It becomes possible due to the presence of paired suprabranchial chambers covered with respiratory epithelium (the skin which is capable of saturating oxygen).
The adult fish and its juveniles can breathe with the atmospheric air.
Difficulties in keeping
The snakeheads are rather undemanding, but as a rule they are quite large and they can prey on small fishes. There are several large sized species, which can dwell in small tanks.
Snakeheads are one of the most interesting in keeping species: they are not demanding in terms of the tank conditions, they are rather intelligent (for the fish), have good appetite, exciting behavior, don’t tend to eat any tank plants.
However, when buying species, keep in mind that the fish is large and aggressive, it can eat everything that it can swallow. Therefore, never believe a seller who says that the snakeheads will do no harm to other tank dwellers.
Most of the fish species can’t be recommended to beginner aquarists due to their large size (over 30 cm long), special requirements to the tank water temperature (the water should be cold in winter time) and intraspecific aggression they demonstrate towards each other.
Keeping in a tank
To breathe snakeheads just like climbing perch species need continuous access to the air between the tank water surface and the tank cover-glass.
In the wild most of species are benthic ones, but in tanks where there are no predators, the fish starts to use all the possibilities the tank provides.
There is a common misconception among the beginner aquarists, that fishes capable of breathing with atmospheric air can dwell in water of poor quality and therefore the tank where they live doesn’t require proper care.
Despite the fact that some snakeheads can stand difficult environmental conditions, you shouldn’t test their endurance by neglecting some basic measures required to maintain the proper tank water quality.
Even if in the wild the fish can survive at unfavorable environmental conditions, the tank water should have optimal parameters for it.
Most of the snakeheads representatives dwell in soft (up to 8 GH) and acid waters (pH 5.0 — 7.0). It is recommended to create the same conditions in the tank.
In captivity, species don’t behave rather actively. They spend significant amount of time in middle and bottom water layers, only from time to time they go up to the water surface to get another portion of atmospheric air.
Keeping in mind this peculiarity of the fish behavior, you should put some shelters into the tank – various snags and tank plants will do.
In the wild when swimming to the water surface the fish puts itself in danger, that comes both from aquatic predators and fish-eating birds (mainly from frog peckers). For this reason, you can always find floating plants where the fish dwells. Therefore, they should be present in the tank as well.
Snakeheads are predators, so they can suddenly make some abrupt movements which make the tank water muddy and as a result the water filter gets clogged. To minimize consequences of such behavior of the fish, it’s better to use small and medium sized gravels as the tank bottom substrate, not sand.
A tank with snakeheads inside should be tightly covered with a cover-glass or a lid with a lamp, since the fish quite often tends to jump out of the water.
Feeding in a tank has its peculiarities. You should not only scatter the food over the tank water surface, but also feed some specific fish species.
You can do it with your fingers or pincers – this depends on the kind and its size.
Most of the kinds are omnivorous, however, it is preferable to feed them with insects and their larvae. The fish will eagerly eat crickets, meal worms and earthworms.
You can train snakeheads to eat meat, shellfish and shrimps, though, artificial food, meat containing one, pellets or sticks will do as well. What can be considered as an advantage, is that the fish doesn’t eat tank plants or any other vegetation.
Gender differences: male vs female
The fish species don’t have any pronounced gender dimorphism. As a rule females have more rounded body shape, than that of the male. If you look from above, the adult male have a bit wider head, but this is a rather low-observable feature.
Taking into account the predatory behavior most of this fish kinds are kept in tanks. Nevertheless, if you put some efforts into this you can successfully keep snakeheads in a community tank.
First of all, you should pay attention to the fish size. Most dwarf snakehead fish kinds will become good tank mates for other large sized fish species.
It’s completely not an option to keep snakeheads with small catfish or loaches, since the fish won’t be able to swallow any of them and it’ll die from choking.
Active and undemanding fish kinds will do as tank mates for most most of average sized species. These can be large and medium sized carp, like KOI.
Despite the predatory nature small sized snakeheads are timid and can be easily killed by large and aggressive cichlid (for example, flowerhorn).
Provided with optimal tank conditions the breed rather easily. Inability to define gender of the juveniles makes aquarists buy several fish species and wait till they form couples and start to keep off other tank mates.
In a group of young fishes once the fish become reproductive, they start to form couples. Then the formed fish couple secludes and occupies a certain territory, which it dedicatedly guards.
Some start to breed spontaneously, others require some additional stimulation by means of cooling and then heating the tank water (imitation of seasons change).
In many snakehead kinds both fish parents take care of their eggs and juveniles, which then stay close to them in a school.
The process of taking care about the juveniles may be a rather long-lasting one. Sometimes, it stops only when juveniles grow to become 5-8 cm long. Only after this the breeders start to make the young species go away from their territory.
Snakeheads tend to demonstrate intraspecific aggression towards each other, that’s why it is important to have enough of shelters in the tank: snags, large stones, ceramic tunes and flowerpots as well as large bushes of tank plants will do for this purpose.
Otherwise, the fish are quite capable to do serious harm to their relatives.
The most challenging stage of keeping in a tank starts when the fish become reproductive. The breeders start to have more fights, at that the female fish usually tends to initiate them.
Snakeheads don’t nip each other’s fins and don’t lock to each other’s mouths like ‘kissing’ (as cichlids and egg-laying cyprinodontid fishes do); the snakeheads hit their rivals hard on the side and as a result whitish marks and exfoliated scales are left on the fish body. Sometimes such fights end up in death of one of the rivals.