Clarias fuscus (Lacepède 1803)

This taxon is one of a number of demersal species in the Yangtze River system. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton. The upper Yangtze basin consists chiefly of Paleozoic limestone and terrigenous sedimentary rock, with some granitic material. The most downstream element of the upper Yangtze basin is often termed the Sichuan Basin; here the Yangtze cuts through Triassic and Permian material before entering the Three Gorges. The Three Gorges area is a stretch of the Yangtze that runs approximately 660 kilometers, terminating at the site of the Three Gorges Dam. Prior to construction of the dam, the Three Gorges area was a site of exceptional natural beauty; after dam construction the gorge areas were filled with approximately 100 meters in depth of Yangtze water, and considerable amounts of the watershed were graded. The lower Yangtze basin consists of anabranching river structures and Pleistocene coastal terraces. Prior to development of the Three Gorges Dam, the Yangtze Delta was replenished with a copious sediment load reaching the river mouth; however, the dam has now severely limited the natural flow and deposition of sediment to the delta region. Consequently, the integrity of the delta is been compromised, with scouring exceeding deposition, and the very stability of the delta is endangered. Lower and middle basins of the Yangtze carry heavy pollutant loads. In the lower Yangtze basin nitrate levels are high, measuring at about 1000 tons per day at Datong; these levels accrue from high applications of chemical fertilizer applied and also considerable loadings of untreated sewage due to the large human population of the basin, with correspondingly little infrastructure for sewage treatment. Heavy metal concentrations are also high in the lower Yangtze, with measurements of dissolved lead at 0.078 microgram/liter; cadmium (0.024 microgram/liter), chromium (0.57 microgram/liter), copper (1.9 microgram/liter), and nickel (0.50 microgram/liter). Levels of dissolved arsenic have been measured at 3.3 microgram/liter) and zinc at 1.5 microgram/liter), both notably higher by factors of 5.5 and 2.5 respectively than other typical large world rivers. In Yangtze River suspended sediment, arsenic comprises 31 microgram/gram, lead comprises 83 microgram/gram, and nickel comprises 52 micrograms/gram of sediment content There are several large native demersal fish found in the Yangtze River, chiefly the 250 centimeter (cm) long endangered Yangtze sturgeon (Acipenser dabryanus), the 120 cm Chinese sturgeon (Acipenser sinensis), the 200 cm Giant mottled eel (Anguilla marmorata), the 122 cm black carp (Mylopharyngodon piceus), the 300 cm Chinese paddlefish (Psephurus gladius), and the 100 cm Silurus meridionalis. Furthermore, there are a few exceptionally large native benthopelagic fishes found in the Yangtze, namely, the 105 cm Silver carp (Hypophthalmichthys molitrix), the 200 cm Wuchang bream (Megalobrama amblycephala), the 200 cm yellowcheek (Elopichthys bambusa), the 145 cm common carp (Cyprinus carpio carpio), the 122 cm Mongolian redfin (Chanodichthys mongolicus), the 102 cm predatory carp (Chanodichthys erythropterus) and the 100 cm snakehead (Channa argus argus).. The demersal fish Silurus meridionalis also is found as a Yangtze River endemic species.

Nude body without scale, sticky. Yellowish brown or dark gray, white and gray stomach. Lateral white dots on the sides (Ref. 40531). Sometimes confused with the channel catfish, but Clarias fuscus can be differentiated by its rounded tail and long dorsal and anal fins (Ref. 44091).

Aeromonosis. Bacterial diseases

Edwardsiellosis. Bacterial diseases

Oviparous (Ref. 205).

Dorsal soft rays (total): 59 - 63; Analsoft rays: 42 - 46

Occurs in streams, ponds, ditches and reservoirs. Feeds at night on small fishes, crustaceans and insects.

Adults occur in streams, ponds, ditches and reservoirs. They prefer deeper pools and tend to hide under thick mats of vegetation; are nocturnal feeders foraging on small fishes, worms, crustaceans and insects (Ref. 44091). Benthic (Ref. 58302). Oviparous (Ref. 205).

fisheries: minor commercial; aquaculture: commercial

產於中國大陸、東南亞、臺灣等地區；但目前以養殖魚為主。

為養殖食用魚。本種通常以枸杞燉之，具食補作用。

體延長，頭部平斜，後部側扁；頭背部具骨板。吻寬而短。前鼻孔為一根短管，後鼻孔則為裂縫狀。上頜較突出。鬚四對，鼻鬚與頦鬚各一對，較短；上下頜鬚各一對，較長。體裸露無鱗，皮膚光滑，多黏液；側線平直，沿體側中部而伸達尾基。背鰭基部長，僅具軟條55-63；臀鰭與背鰭同形，其軟條39-46，不與尾鰭相連；胸鰭小，但具1根粗狀硬棘，其內緣呈鋸齒狀。體黃褐色或灰黑色，腹部灰白色；有時體側另具10條由5-6個細小白點的縱紋。

棲息於河流、溝渠、湖沼與稻田等具泥質地之水體中。常群集於岸邊暗處或洞穴中，能長期間離水，遷移能力強。為夜行的底層活動魚類，食性廣，不僅捕食小魚、蝦，也攝食腐敗的動植物碎屑。雄魚會築巢與護幼之行為。