Rhinogobius flumineus (Mizuno, 1960)
Rhinogobius flumineus
photo by Suzuki, T.

Family:  Gobiidae (Gobies), subfamily: Gobionellinae
Max. size:  7 cm TL (male/unsexed)
Environment:  benthopelagic; freshwater, non-migratory
Distribution:  Asia: Japan, from Shizuoka Prefecture and Toyama Prefecture westward to Honshu, Shikoku, and Kyushu.
Diagnosis:  Vertebrae: 27-28. First dorsal fin with 4th ray longest and large, square bluish-black mark on anterior 2/3 of first dorsal fin in male; first dorsal fin with 2nd and 3rd rays longest and pale lacks this large dark mark in male (Ref. 79602).
Biology:  Adults inhabit middle to upper reaches of rivers, and are especially found in open and shallow areas. Breeds from June to August and makes a spawning bed (nest). Eggs are protected by the male. As soon as they hatch, the juveniles live on the river bottom. Not amphidromous. Food fish.
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless

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