Wiktionary
fishbelly
n. 1 The belly of a fish. 2 An early kind of cast iron rail for railways, predating the bullhead rail.
Usage examples of "fishbelly".
The Wyrm was scaled and plated, but in a thick fishbelly blue-white rather than any Dracon green or gold or red.
But it was good to be in the sun, anyway, the heat on my skin, drying me, tanning me around the middle where I was fishbelly white.
Instead they were pasty and fishbelly white, and their movements as they reached out to grapple the dead jellies were stiff and mechanical, with none of the feathery grace of the live tendrils.