Cypriniformes: Cyprinidae
Opsariichthys hainanensis Nichols & Pope, 1927
‘Catalog of Fishes’ synonyms
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Opsariichthys hainanensis Nichols & Pope, 1927
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original designation
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Chinese (Mandarin)
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海南马口鱼
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German
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Hainan-Raubkarpfen
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The specific epithet ‘hainanensis’ means ‘from Hainan’.
max. 128 SL; 115 mm SL, holotype (Nichols & Pope, 1927).
Figure 2. Opsariichthys hainanensis: nuptial male, lateral view, EZ-CN 18-06, Hainan Island, China.
DIII,7-8; AIII,9-10; PI,13-15; lateral line scales 40-41; predorsal scales 16-17; gill rakers 10-11; total vertebrates 39-41; lower jaw prominent; anterior tip of upper jaw with a deep central notch; maxillary extending to a line through the mid of orbit in adults; body depths 27.5-30.9% in males; adult males with 9-11 vertical green-bluish bars of irregular width on flanks (Chen et al., 2008).
Strong sexual dichromatism and -morphism.
Inhabiting riverine environments with slow to fast current over gravel and rock substratum; clear and transparent water; pH 7.0-8.4; 27-30.8 ºC; 63-124 µS/cm (pers. obs., March 2006, Hainan Island, China).
Shoaling; bentho-pelagic to pelagic; syntop with Ctenogobius cervicosquamus Wu, Lu & Ni, 1986 in ELZ-CN 02-06, Hainan; syntop with Micronemacheilus pulcher (Nichols & Pope, 1927) in ELZ-CN 03-06, Hainan, always riverine water systems; shoals of up to 30 individuals in shallow waters when juvenile; shoals of 5-12 individuals in deeper water, 20 cm above substratum, when adult; permanently swimming (pers. obs., March 2006, Hainan Island, China).
Lithophilic bottom spawner; typical S-position, eggs buried by a swift front ward motion when spawning; fry feeds on zooplankton below water surface(pers. obs., 2006-2008, in aquaria).
Carnivorous; active hunting; facultative piscivorous when adult; facultative insectivorous when juvenile (pers. obs., 2006-2008, in aquaria).
IUCN Red List not evaluated.
Adults requires large tanks with a min. length of 120 cm; space for swimming, need plentiful supply of feeder fish when 80 mm TL; biologically and mechanically filtered water; massive water changes; easy to bred; fry is too small to be regarded as prey.
Populations of the four major river basins on Hainan Island are genetically distinct, all of them are considered genetic lineages but conspecific (Chen et al., 2008).
Anal fin colored, enlarged, with projections extended in males; vs. not extended, pale in females. Dorsal fin colored and enlarged in males; vs. not extended, pale in females (Chen et al., 2008; pers. obs., March 2006, Hainan Island, China).
Endemic to Hainan Island, SW China.
Caudal fin yellow in juveniles (pers. obs., March 2006, Hainan Island, China).
O. hainanensis have been recognized as a junior synonym of O. bidens Günther, 1873 since its original description in 1927. Chen et al. revalidated the taxon in 2008 (Chen et al., 2008).
Figure 3. Opsariichthys hainanensis: female, adult, lateral view, EZ-CN 18-06, Hainan Island, China.
Figure 5. Biotope EZ-CN 18-06; 5 km W of Daanzhen (打安镇), towards Bai Sha (白沙, Hainan Island, China.
Figure 6. Opsariichthys hainanensis, fry, EZ-CN 18-06, Hainan Island, China.
Figure 7. Opsariichthys hainanensis, male, head profile, allocation of breeding tubercles, EZ-CN 18-06, Hainan Island, China.
Figure 8. Opsariichthys hainanensis, female, head profile, EZ-CN 18-06, Hainan Island, China.
Figure 1. Opsariichthys hainanensis; preserved; EPC 0222, nuptial male above, 99 mm SL; EPC0340, female below, 107 mm SL; lateral view, EZ-CN 18-06, Hainan Island, China.
Figure 4. Biotope of Opsariichthys hainanensis
EZ-CN 18-06, 5km W of Daanzhen (打安镇), Hainan Island, China.
