A Summer Flounder on Long Island's Great South Bay

What’s That One Fish With the Eyes Close Together? The fish with the eyes close together you’re likely thinking of is the flounder, a remarkable flatfish species known for its side-swimming behavior and unique eye placement.

In flounders, one eye migrates to the other side of their body as they mature, allowing them to rest flat on the ocean floor while keeping both eyes on their surroundings.

What Makes the Flounder’s Eyes So Unique?

Flounders and other flatfish, such as soles and halibuts, undergo a fascinating transformation called eye migration.

When they hatch, they resemble normal fish, with an eye on each side of their head.

As they grow, however, one of the eyes gradually shifts to join the other, resulting in both eyes being on the same side.

This migration allows flounders to lie flat on the seabed, blending into their environment while keeping an eye on predators and prey.

According to marine biologist Dr. Michael Taylor, “This evolutionary adaptation is one of the most striking examples of how environmental pressures shape organisms. Flounders evolved to blend perfectly with the ocean floor, and their eye placement gives them a distinct advantage as ambush predators.”

Their remarkable camouflage and ambush techniques make them highly successful hunters in shallow coastal waters.

Types of Flatfish with Close-Set Eyes

Several flatfish species exhibit this extraordinary trait of eye migration. Some of the most common types include:

  • Flounder: Known for their sideways swimming and ability to blend into sandy and rocky bottoms.
  • Sole: A popular flatfish species, prized in culinary circles for its mild, delicate flavor.
  • Halibut: The largest of the flatfish family, halibuts can reach enormous sizes but still display the classic eye migration.
  • Turbot: A highly sought-after flatfish in the culinary world, renowned for its diamond-shaped body and firm texture.
  • Plaice: Plaice, a popular flatfish in the UK known for its orange spots, rounded dorsal fins, and distinct head, is favored by both commercial harvesters and sea anglers.

Why Do Flatfish Have Eyes on One Side?

The adaptation of having both eyes on one side of the head is a product of evolution.

As flatfish evolved to live on the seafloor, lying flat on the bottom allowed them to hide from predators while also providing an advantageous hunting position.

With both eyes on one side, they could remain camouflaged while keeping a lookout for potential threats or prey swimming above.

As Dr. Sarah Gordon, an expert in evolutionary biology, explains, “The eyes of flatfish like the flounder are a prime example of adaptive evolution. Over time, these fish developed traits that perfectly fit their niche environment—close-set eyes for camouflage and effective hunting.”

This unique adaptation allows flatfish to thrive in various environments, from coastal estuaries to deep-sea habitats.

Other Fish with Unique Eye Characteristics

Although flounders are most famous for their close-set eyes, there are several other fish with unusual eye placements or adaptations that allow them to see in unconventional ways:

  • Four-eyed Fish (Anableps): A fish native to rivers in South America, its unique split eyes enable it to see above and below the water simultaneously.
  • Stargazers: These fish have eyes on the tops of their heads, allowing them to lie buried in the sand while keeping watch for prey overhead.
  • Barreleye Fish: This deep-sea fish has transparent, dome-shaped heads with upward-facing tubular eyes that can rotate to spot prey from above.

The Importance of Eye Placement in Fish

Anableps on water

For many fish, eye placement is critical for their hunting and survival strategies.

Fish like flounders and halibuts use their close-set eyes to stay hidden on the ocean floor, while species like the barreleye and four-eyed fish use unique adaptations to see in both air and water or peer through the dark depths of the ocean.

Fish anatomist Dr. Paul Stevenson points out that “eye placement is often closely tied to the environment and lifestyle of the fish. Those that live in more stationary, bottom-dwelling habitats, like flounders, need an eye arrangement that gives them maximum vision while staying hidden.”

Learn more about fish anatomy on Wikipedia and the ways fish have evolved to survive in various aquatic environments.

Conclusion

When it comes to fish with close-set eyes, the flounder stands out as a unique example of evolutionary adaptation.

Their eye migration and sideways swimming behavior allow them to blend seamlessly into the ocean floor, making them effective hunters and survivors in their environment.

To learn more about the fascinating world of flatfish, visit Wikipedia’s page on flatfish.

FAQs

1. What other fish have eyes close together?

Other flatfish species like halibuts, soles, and turbots share this trait, all belonging to the same family of bottom-dwelling fish.

2. Why do flounders have eyes on one side of their body?

Flounders undergo a process known as eye migration during development, where one eye moves to the other side of their head. This helps them remain camouflaged while observing their surroundings.

3. How do flatfish use their close-set eyes for hunting?

By lying flat on the ocean floor and using their close-set eyes to watch for prey, flatfish can launch a surprise attack on unsuspecting prey swimming above them.

4. Are there any other animals with similar eye adaptations?

While flatfish are known for their eye migration, other species, like the stargazer and barreleye fish, have unique adaptations that allow them to see in different ways based on their habitats.