今天在家裏閱讀Metropop，發現一個有趣的問題。由於文章裏的美食專家都不曉得原因也沒有說明答案，故引發了我的求知慾。以下是一些解釋：

Salmon flesh is generally orange to red, although there are some examples of white fleshed wild salmon. The natural color of salmon results from carotenoids - astaxanthin and, to a lesser degree, canthaxanthin - in the fish flesh. Wild salmon get these carotenoids from eating krill and other tiny shellfish.

Salmon is a pale pink-red color, named after the color of salmon flesh. Actual salmon color varies from almost white to deep red, depending on their levels of the carotenoid astaxanthin due to a rich diet in krill and shrimp. The widely-accepted color ”salmon” is on the lighter rather than the darker side of this range. (wikipedia)

The pink to orange color of salmon fresh during this period is caused by a carotenoid pigment in the skeleton of the euphausiid (for more about euphausiid shrimp, see chapter on Krill). This flesh color has become so popular that now there are fisheries for euphausiids, which are freeze-dried and fed to pen-reared salmon as a finishing product to produce this color. (geopubs.wr.usgs.gov/circular/c1198/chapters/146-149_Salmon.pdf)

哦，原來係咁......我咁鍾意吃三文魚, 會不會......haha