Hi plaalye!
I can distinguish S.japonicus from S.lagocephalus easily.
S.japonicus has a lateral stripe design without disappearing since the age of a child fish.
The design is a pattern such as "\\\\\\\ //////".
S.japonicus does not seem to change most of the designs of the body, but S.lagocephalus can change a color of the body busily.
The following photo is childish fish of S.japonicus which just went up from the sea to the river.
This is a 2-year change of the same S.japonicus individual.
The next picture is a figure three years before and the recent figure, same individual of S.lagocephalus .
S.lagocephalus can completely delete the pattern of the body.
S.japonicus and S.lagocephalus.
S.lagocephalus and Sicyopterus.sp(Mountain Rock Goby)
Though S.lagocephalus change the pattern of the body, a specific pattern appears.
The scientific name "lagocephalus" seems to mean the head of the rabbit in Greek.
May you find the white pattern like "a head of rabbit" in the tip of nose of S.lagocephalus?
Or the big white pectoral may be likened to the ear of the rabbit.
Sicyopterus.sp(Mountain Rock Goby),..................S.lagocephalus,......................................S.japonicus
Sicyopterus.sp(Mountain Rock Goby),
S.lagocephalus,
S.japonicus
Sicyopterus.sp(Mountain Rock Goby), .............................................S.lagocephalus,
S.longifilis,........................................................................... S.japonicus
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