How did Paralichthys dentatus come to stand in for luck?
Described as “a flatfish noted for its fighting ability and flavor…[which] has both eyes on one side of its head and rests on the ocean floor on its side….Summer flounder are called the chameleons of the sea because of their ability to change color to match the bottom on which they are found….[They grow up to be] very active predators, often chasing schools of small fish to the surface and leaping out of the water in pursuit of them. This behavior clearly distinguishes the summer flounder from the other more sluggish species of inshore flatfish.”
“lucky chance,” 1857, originally a lucky shot at billiards. Maven’s Word of the Day concurs.
Something described as fluky, however, is “1. Resulting from or depending on mere chance. 2. constantly shifting; uncertain: a fluky wind.”