Reinhardtius hippoglossoides is a flatfish that lives in the northern part of the Atlantic Ocean. It can grow up to 1 m long and weigh 20 kg.
The fish belongs to the flounder fish, but differs from the other flounders by being less attached to the bottom and by also swimming with the belly side, and not with the blind side, down. As a result, its left eye is not completely horizontal on the eye side, and both body sides are colored and muscular.
It is widely circumpolar and is thus found in both the North Atlantic and Pacific Oceans.

Halibut is often eaten as either smoked or marinated, instead of the very common salmon.