Channa argus

{pronunciation} are-guss

Common name:

Amur snakehead. (C.argus warpachowskii)

First description:

Cantor, T.E. 1842
Ophicephalus argus.
'General features of Chusan with remarks on the fauna and flora of that Island'.
Annals and Magazine of Natural History. Volume IX: p.484.

Meristic:

D: 48-53 A: 30-38 C: 14 V: present Ratio (Body/ head length) : 2.9-3.2*
(* Although as the fish ages its relative proportions change)

Lateral line scale count:

60-75

Description:

The upper surface has a brownish-green background colour and numerous (9-13) black blotches. These have a lighter centre that is sometimes edged in white, above the lateral line. There are bars under the dorsal base (dependant on age). The mid-section is a yellowish-grey while the reddish-white abdomen has streaks above the anal (dependant on age).

The upper parts of the head have three paired bars and on the sides can be seen two broad stripes; one starting at the snout, running through the eye to the gill cover, whilst the lower curves downwards and ends at the edge of the gill cover.

The fins are yellow, the dorsal, anal and caudal are spotted black.

Size:

The largest size recorded in literature is 800 mm and a fish of 8 years old was recorded at 760 mm.
(Amanov 1974)

Sub-species and colour variants:

Channa argus kimurai (Shih 1936)

This fish was described from two specimens of length 185 mm and 250 mm and can be distinguished by its variation in body proportions. In particular, the lower dorsal profile and differences in the arrangement of teeth. The body colour is all white, a complete contrast to C.argus. Above the lateral line, some of the scales have a grey centre. Vertical fins are tipped grey.

Channa argus warpachowskii (Berg 1949)

This larger variant can attain a size of 800 mm and a weight of 7 kg. Differences are; higher than average ray counts in the dorsal (50-53) and anal (33-38) fins, and smaller scales. The irregular blotches on the side of the body are dark brown, edged with black and the lower part of the head is covered with small, dark brown speckles.

General Synonyms:

Ophicephalus argus, Ophiocephalus argus, Ophicephalus nigricans, Ophicephalus pekinensis.

Geographical location:

In the original description, C.argus was reported from Chusan, China and this has been confirmed by Shih (1936) who stated that it is the dominant snakehead in China. This Snakehead can be found in rivers, streams and ponds across China, from Yunnan to Peking.

C.argus kimurai is said by Shih (1936) to inhabit the River Kialing in the Szechuan province, also in China; where it is said to be common in the rice fields as well as mountain streams. Reeves (1927) states that C.argus can be found to the North-East of China and Korea. From further north, into Russia, in the region of the River Amur, hails the hardier C.argus warpachowskii which has been successfully introduced to many countries, including the former Czechoslovakia.

Maintenance:

Obviously a very large and robust fish tank is needed to maintain a fish of this size, so most specimens are kept in public aquariums.

Channa argus warpachowskii have been kept alive under ice, in ponds and also Frank (1970) mentions that they have survived temperatures amounting to 40 °C, but in the aquarium a temperature between 14 and 22 °C is sufficient. Due to its ability to survive in the most severe habitats, carefully maintained water conditions are not essential.

In the Chimkurgan Reservoir, USSR, C.a.warpachowskii was studied by Amanov (1974) where it was found that fish over 20 cm long, feed exclusively on fish, including small cyprinids, rudd and white bream, whilst younger fish fed on invertebrates, chironomid larvae and consumed large quantities of tadpoles.

Breeding:

Sexing of this fish by external appearance is hard, and can only be done when the fish are fully grown, the males being larger than the females. Despite this fact, Channa argus warpachowskii becomes sexually mature at an approximate size of 30 cm, when it has attained an age of 2 years.

If breeding is to be attempted, a tank or pond holding at least 3,000 litres is needed. Frank (1970) mentions that unless this fish has been kept in generous quarters, it will become stunted due to insufficient space and the larger specimens develop a shy nature.

Observations of this Snakehead breeding in its natural habitat show that a large floating nest (up to 100 cm in diameter) is constructed, consisting of plant fragments. This can be mostly found in fairly shallow water with dense vegetation. After spawning, an average of 50,000 eggs are fertilized. Nearly three-quarters of the egg contents consists of oil, so the eggs float freely to the nest. Here they are guarded by the male. At a temperature between 23 - 25 °C and after a period of 36 hours they hatch from the egg.

Three days later the young fry have absorbed their yolk sac and at the size of 7-8 mm, they will start searching for small water insect larvae. After that, they consume large quantities of smaller fish, tadpoles etc. and by the end of their first year, will attain a a size of 20 cm.

Due to its very good growth rate, it has become a popular food fish and presently there are several researchers in U.S.S.R. and China contributing to studies on this fish; namely Amanov (1974)
and Soin (1960).