Great question! Did you know that scientists at UCSB are asking this very same question? They would like to understand how these fish (and other marine animals like them such as octopi and squid) do this so that they can develop camouflage technologies or other technologies such as solar panels and materials that reflect or capture light. By the way - have you seen a peacock flounder in it's native habitat in the Indo-Pacific oceans? I hope so - they are really beautiful!

The basic answer to your question is that the fish has specialized cells in its skin that contains various pigments (compounds that have color) - these cells are somehow wired into the vision of the fish. Whatever the fish "sees" is transmitted to the cells and they adjust the pigmentation to match the environment.

Scientists don't understand exactly how this happens, but you can do an experiment to test the connection between the eyes and the cells with the pigment. Can you guess how?

Yep - scientists can cover up one eye with sand (for example) and the fish has a really hard time matching its color to the environment.

There are lots of ways for animals to camouflage or to change color in response to stimuli (especially for mating) and we are just now starting to understand the molecules and the biophysics of how that works. Scientists and engineers are really curious about it because it might give us new ideas about how to make better or new devices - this is called "Bio-Inspired Materials." Scientists are also just plain fascinated by how these beautiful creatures change color - just one more question about the amazing world that we live in!

So an animal’s ability to change color to match its environment is an interesting and still not entirely understood subject. One animal that changes color that we are starting to understand is the squid. Living things are made of many little living pieces called “cells.” Different cells have different purposes in a living thing: some are responsible for carrying oxygen around the body, some help the heart beat, and others make up our brain. The cells on the surface of a squid react to stuff happening in their environment; that stuff in the environment tells them to do something and is called a “stimulus.”

When light is reflected off of a surface that a squid is on, that light tells the cells on the surface of the squid to change color or shape. The result of this is that the squid looks like the surface it’s on. It is likely that a similar process happens in the peacock flounder.

Peacock flounders change color to camouflage with their surroundings to reduce the chances of being noticed by their predators, so they don't get eaten, and their preys, so they can creep up and hunt their prey. They are able to change color in a matter of seconds to adapt to the environment change.

The exact process in which it changes colors is unknown, but scientists say it is related to the flounders' vision, because it has to see the color of the environment its in, and the hormones it releases, to be able to surface the certain pigments onto its skin.

Peacock flounder are an unusual fish. They are one of the few fish species that can change their color to match their environment. Other ocean animals can do this, such as octopus and cuttlefish. It is not completely clear how these animals are able to change there color to match their environment. It looks like peacock flounder use their eyes to see the pattern in the environment and then change the pigments that show on their skin to match their surroundings. But octopuses (yes, the more correct plural or octopus is octopuses, not octopus) don't need their eyes to change their skin color. The skin will respond the changes in the environment without the eyes and brain "telling" it. But these are some really new and interesting fields of study. Scientists don't completely understand how it works.