In the wild, fish have to protect themselves from predatory fish so what better way than to use camouflage to do that. This can involve blending in the background, adopting a dull color when they are juveniles and not able to protect themselves from predators, and more. To blend into their background many fish will do contour elimination or color matching.

How Fish Use Camouflage

Fish not only use camouflage to protect themselves from predators but also use it as a way to get their food easier. Being camouflaged, they can sneak up on their food and get it before it swims away. 

How Fish Camouflage in the Natural World

How fish match the colors in their environment will differ between species. Some fish have managed to perfect the chameleon art of reacting and then changing to what their immediate surroundings are. This is referred to as adaptive camouflage. Other species will just adopt a drab overall color. These means of camouflage are most often seen in fishes that live near or on the substrate, which is the bottom of the ocean. The fish that is the master at these types of camouflage is the marine flatfishes but some catfish and loaches can also do this. 

For fish that live in the main water column, like the silver dollars and penguin fish, their silvery scales can reflect the colors and light of the underwater world. Some fish like the glass catfish have virtually transparent bodies that act like camouflage by letting the dominant colors of the habitat to show through them.

Some fish use light-catching camouflage abilities. This is called reflective crypsis. It can employ many methods such as reflection, transparency, and counter-illumination to keep themselves hidden from predators, even at the deepest depths of the water.

Maximizing the Benefits of Camouflage

In order for the camouflage the fish are using to be effective, they have to find a way of pulling it off by breaking up the contours and outline of their body. 

• Counter-shading — with this method of camouflage, the belly is light and the dorsal surface is dark. This will allow the fish to blend in when it is seen from below when pictured against the sky and from above against a deep background.
• Disruptive coloration — when the color pattern of the fish has such features as stripes, this method will allow different parts of the fish’s body to blend into the background. When it does this, it will break up the outline of the fish. Some of the fish that use this type of camouflage are tiger barbs, angelfish, and kuhli loaches. This means of camouflage is good when used against a background of plant stems that are vertical. This might be the reeds at the edge of the water. 

Fish That Use Camouflage

• Reef Stonefish — these are also known as rockfish and is one of the most venomous fish found in the world today. You will find them in the shallow waters in the Indo-Pacific region and live on the reef bottoms. They will act and look like corals or rock and when small fish or shrimp are looking for food, the Reef Stonefish will ambush them for food. With their large pectoral fine, they can also bury themselves in the sand.
• Trumpet fish — this fish is good at sneaking up on their prey. They can swim vertically in a swaying rhythm and give the image of a floating stick. The prey is caught unaware when they suck them up. They can also take a vertical position in order to mimic the shape of corals that are around the fish.
• Lionfish — this is a venomous species that is very poisonous and their sting can cause severe pain, even death in some cases. The common lionfish has a transparent dorsal fin covered with dark spots. This will allow the fish to blend into its surroundings like gorgonian and coral fans. At this time, there are over 12 species of lionfish and all have different patterns and colors.
• Painted frogfish — this fish has the same superpowers of the chameleon in that it is able to adapt to its surroundings. It does this by changing color based on their environment. They are found in the Indo-Pacific region on coral reefs and rocky areas. The frogfish’s extensible body is covered in stripes, blotches, filaments, and spots. All of this will help them to imitate their surroundings and stay hidden from predators. The frogfish is about 30cm and has legs and skin that resemble frogs.
• Leafy sea dragon — this is another marine species that is great at camouflaging and belongs to the same family as the seahorse. The fins of the leafy sea dragon are almost transparent so it is almost hard to see them. When they move along the water they appear to be floating seaweed. They also curl their tails into sea grasses or weeds to stay safe if there is a storm. It keeps them from being washed ashore. These fish have a yellow, brown, or green coloration so it helps them to blend in well with seaweed plus they also have flowing appendages that look like seaweed. They are about 12 inches long.
• Flatfish — these fish change color according to their environment and they also like to bury themselves to catch prey or to keep from becoming prey.

Conclusion

• Predatory fish can also use camouflage so they can sneak within striking distance of their prey. 
• One major component in underwater camouflage is light refraction. With little to no sunlight at the bottom of the ocean, it is a mystery as to how the fish can use this type of camouflage.
• Some fish absorb light so proficiently that they look like silhouettes even in bright light with little to no features that are distinguishable.
• Camouflage is used in two ways in the ocean; to protect themselves and to be able to sneak up on their food without being seen.
• Almost every marine species uses some type of camouflage.

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