Perccottus glenii Dybowski, 1877
Chinese sleeper
Perccottus glenii
photo by Sediva, A.

Family:  Odontobutidae (Freshwater sleepers)
Max. size:  25 cm TL (male/unsexed); max.weight: 250.0 g; max. reported age: 7 years
Environment:  demersal; freshwater; brackish
Distribution:  Asia: Tugur (Sea of Okhotsk) and Amur southward to Yangtze and Fujian. In Amur, historically known from the middle and lower Amur (from Tygda Rive down to the estuary) with tributaries Zeya, Sungari, Ussuri and the Khanka Lake basin. Reported from Shilka in the upper Amur where it is introduced (Ref. 82587). Introduced in Europe (Ref. 59043). At least one country reports adverse ecological impact after introduction (Ref. 2058).
Diagnosis:  Dorsal spines (total): 6-8; Dorsal soft rays (total): 9-11; Anal spines: 1-3; Anal soft rays: 7-10. Distinguished from other European freshwater species by the following characters: 2 dorsals with the first with 6-8 simple rays, and the second with 2-3 simple and 8-12 branched rays; no spines on first dorsal; no barbels; pelvics not fused into a disc; no lateral line canals; males during spawning period, develop a hump on nape and become black with bright green spots on body and unpaired fins (Ref. 59043).
Biology:  Occurs in lentic waters, lakes, ponds, backwaters and marshes with dense underwater vegetation and avoids river stretches with fast and even slow current (Ref. 59043). Prefers stagnant rivers and bogs (Ref. 80031). Can tolerate poorly oxygenated water and able to survive in dried out or completely frozen water bodies by digging itself into mud where it hibernates. A voracious predatory fish (wide variety of invertebrates, tadpoles and fish) constituting a most serious threat to aquatic fauna wherever it occurs. In small water bodies; known to extirpate almost all other fish species and amphibian larvae. Spawns for the first time at 1-3 years and about 6.0 cm SL. Spawns several potions of eggs in May to June at 15-20°C. Elongated eggs (3.8 x 1.3 mm) with sticky filaments usually deposited in one row close to water surface on underwater structures such as roots, leaves and others. Males guard the eggs and pelagic larvae (Ref. 59043).
IUCN Red List Status: Least Concern (LC); Date assessed: 09 March 2020 Ref. (130435)
Threat to humans:  potential pest


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