The Halibut is the largest flatfish in the ocean. This species can grow up to nine feet in length and weigh as much as 600 pounds. While most people assume that their eyes would be on opposite sides of their heads, it is actually quite different. 

The Halibut is born just like any regular fish. They have eyes and nostrils on both sides of their head. But as they mature, their eyes move towards the right side of their head. This results in having two eyes on only one side of the fish.

Why Do Their Eyes Move? 

The Halibut is part of the flounder fish family. Flounders are demersal fish, better known as fish typically living on the sea bed. The Halibut is born with their eyes on each side of their head, just like most fishes. 

Young halibuts feed on plankton and other small sea creatures. But as they mature, they move to the seabeds. When they do so, their bodies adapt to their habitat. (Source: Animal Sake)

Their genetics greatly assists their adaptation. The bones on the left side of the fish’s skull grow significantly faster than the right. This unusual growth pattern causes the left eye and nostril to migrate to the right side of the head. But interestingly enough, their jaws do not follow the unusual development, leaving the fish to bite vertically. (Source: Oceana)

All About the Halibut 

Halibuts are typically found on the seafloor of the continental shelf. As they are demersal fish, halibuts are considered good ambush predators. They patiently wait for their prey to be within attacking distance before they attack, instead of other predatory fish that go after their prey.

As they adapt to living on the seafloor, they develop patterns on their skin that blends well in their surroundings. The Halibut are typically brownish with dark patterns, but some are brighter. Their unusual development also leaves their other side, which becomes their bottom side, white.

Halibuts would dig into the seafloor to camouflage themselves as they wait for their unsuspecting prey. Their eyes remain visible as it is bulging from their heads. 

The Halibut would grow into massive sizes. Their diet often consists of other fish like capelin, cod, herring, haddock, squid, smaller crustaceans, or pretty much any other sea creature they can swallow.

Interestingly, the Halibut do not engage in mating rituals. Instead, they breed with a method called broadcast spawning. Females release their eggs into the water column in the same area where the male halibuts release their sperm. The process increases the success rate of fertilization and, at the same time, protects its eggs from being eaten by egg predators. (Source: Animals)

Is The Halibut Safe to Eat?

A variant of Halibut, known as the Pacific halibut, has become increasingly popular in culinary circles. It has firm meat and has been delicious regardless of how it was prepared. Halibuts have low body fat and high selenium, niacin, and phosphorus doses.

However, researchers point out a few reasons to avoid this fish. Here are some of them.

Overfishing – The Atlantic Halibut is on the avoid list because its population has significantly dwindled due to overfishing.

High mercury levels – The Halibut is known to be rich in mercury levels. Researchers found that the Atlantic Halibut is more prone to have unsafe and toxic levels of mercury and harmful industrial chemicals it unknowingly ingests. This makes it dangerous for human consumption, especially to children and pregnant or nursing women. (Source: Dr. Axe)