Correct those would be the "white lemon pearl" although that seems to be a name made up for the english market, and considering the vague and confusing information floating around I suspect this was intentional to stop people from finding out where they are from. Either the sellers of these fish were intentionally holding back information or just didnt look into it because clearly they are comming off farms that know EXACTLY what they were.
Guatneee 100% argus, no doubt any more, it's being farmed for over a decade now. Plenty of studies and information on them (in Chinese) i even found the genome sequencing.
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Here is a clip that goes with the picture for comparison, you see the farm that produces the white fin variety simply calls them "special white" (keep in mind it's choppy because i used google translate)
Special white mullet relatively ordinary white mullet so special is that it reared under the same conditions, more disease resistance, more active, more rapid growth.
Special white mullet dorsal stripe, anal fin, caudal fin of transparent gold color, the head of the Ministry of silvery white, other parts are snow white.
Ordinary white mullet dorsal stripe, anal fin, caudal fin of an off-white, off-white head of department, other parts are white.