The fish in the Aquarium come in all shapes and sizes, but if you’ve ever looked closely at our Gulf of Maine exhibit you may have noticed some funny-looking faces hiding in the sand.

Flatfish—including the winter and summer flounders (Pleuronectes americanus) and (Paralichthys dentatus), and Atlantic halibut (Hippoglossus hippoglossus) found in our exhibit—have eyes on only one side of their bodies and a mouth that appears to open to the side.

Winter Flounder Face
Winter flounder (Pleuronectes americanus)

These fish didn’t always look this way! As larvae, they have symmetrical faces, which means they look like most of the rest of the fish in the Aquarium, with an eye on each side of their body. As a flatfish grows into an adult, one eye migrates across its head and onto the “top” of the body, but its mouth stays in the same place—this gives flatfishes their distinct sideways look.

Once the eye metamorphosis is complete, the fish lays its blind side on the sandy bottom. Its mottled brown coloring helps it camouflage with the sandy surroundings, letting it lie in wait for its next meal.

Summer Flounder blending in with the sandy bottom.
Summer flounder (Paralichthys dentatus)

Stop by and see if you can spot them in the sand!