Green around the gills.... is it possible?

Factual Questions
1

Gills are full of blood. I would think it would take serious putrefaction to make them turn green… or is it even possible?

2

Feeling sick is the point of the saying. Green is associated with nausea for some reason. And “gills” is essentially slang for the sides of the human head. We certainly have never managed to get a fish to tell us how they feel.

3

Of course the expression doesn’t refer to real gills, but to the fact that when you’re ill you get pale, and the sides of the neck and face may appear faintly greenish.

I doubt it’s possible for vertebrate gills to look green. However, some worms have green blood and hence do have green gills.

4

“Around the gills” doesn’t have to mean the gills themselves are green. Opaleyes are greenish, so they should qualify. So should the Creature From the Black Lagoon.

5

I am extremely pale to begin with, and look distinctly green when I am sick. I am not a fish.

6

Huh? Why would anyone appear green (faintly or distinctly or otherwise) under any circumstances? Is it the copper-based hemoglobin?

7

Hemoglobin is iron-based, not copper-based.

Veins appear blue under the skin (although the blood in them is red). Since veins are closer to the skin than arteries, if your skin becomes pale it can take on a greenish cast due to the veins.

8

From the Oxford English Dictionary:

Gill, n.

  1. Applied to various organs, etc. resembling the gills of a fish.
      2.a The wattles or dewlap of a fowl.

  2. Attributed to persons:
      3.a with jocular allusion to the capture or holding of a fish by the gills.
      3.b with allusion to sense 2 a: The flesh under the jaws and ears; esp. in phrases to be rosy about the gills, to look in good health; to be white, blue, yellow about the gills, to look dejected or in ill health; to turn red in the gills, to show signs of anger or indignation.

    1626 Bacon Sylva §872 Anger‥maketh both the Cheekes and the Gills Red. 1632 B. Jonson Magn. Lady i. i, He‥draws all the parish wills, designs the legacies, and strokes the gills Of the chief mourners. 1681 Dryden Span. Friar ii. ii, He says he’s but a friar, but he’s big enough to be a pope; his gills are as rosy as a turkey-cock. 1798 C. Smith Young Philos. III. 274 ‘My dear Sir!’ replied Sir Appulby, in visible confusion, his fat gills quivering, and his swollen eye-lids twinkling [etc.]. 1812 Sporting Mag. XXXIX. 102 [He] grew white about the gills. 1816 Wolcot (P. Pindar) Wks. I. 8 Whether you look all rosy round the gills, Or hatchet-fac’d like starving cats so lean. 1842 C. Whitehead R. Savage (1845) II. viii. 277 You won’t run away with her, I hope, and leave my old gills to be cuffed, will you? 1855 Thackeray Newcomes II. 58 He looks a little yellow about the gills. 1893 ‘Q.’ [Couch] Delect. Duchy 168 He‥looked very yellow in the gills, though clearly convalescent. 1894 Du Maurier Trilby (1895) 236 How red and coarse their ears and gills and cheeks grew, as they fed!