Seafloor Dweller, E.g. Flounder, Plaice
Puzzle 10 of Running a Marathon Pack
Question is: Seafloor Dweller, E.g. Flounder, Plaice
and the answer is: FLATFISH
Word Meaning:
FLATFISH — A fish of the order Pleuronectiformes, the adults of which have both eyes on one side and usually swim with the other side down, such as a flounder, a halibut, or a sole.
Definitions from Wiktionary.