Another mystery today. These are labelled as 黄尾鱼 (huáng wěi yú) which translates as “Yellowtail fish’. Given that hundreds of different species are labelled as ‘yellowtails’, this is less than unhelpful.
They are about 15 – 18 cm / 6 - 7 inches long and I would classify them as an oily species, similar in taste to mackerel, but not so strong. I like them a lot and would love to finally nail down an identification.
They are usually gutted and fried whole, but would work well on a grill, too I suppose.