Flat fish

Flat fish, such as Flounder and Sole, are occasionally seen in the aquarium trade and can make an interesting addition to a community tank. Flat fish have a unique development. When they first hatch, they are normal fish that are not bottom dwelling, instead floating free like plankton while they develop. As they grow into adulthood they begin to metamorphose into their adult forms. They will begin to swim more on their right or left side, depending on species, and one eye will travel over the head and onto the upwards facing portion of the body. The side of the fish that faces the ground will begin to lose color while the upwards facing side will develop camouflage and color. Some fish take this development to such an extreme that only half of their mouth develops teeth. In some cases, the eyes of the fish are raised up and allow the fish to see in 360 different degrees; one eye looks left while the other looks right. When introducing these fish to your aquarium, it is important that they be provided with a soft, sandy bottom for them to rest on so they are comfortable. These are bottom dwelling fish that may injure themselves on hard rocks.

Sub-Species for Aquariums:

Peacock Flounder – The Peacock Flounder or Flowery Flounder is so named because of the flower-like blue spots on its body that serve as camouflage against the ocean floor. They lay with their right side against the ocean floor and the left side facing up with their eyes extended on small stumps. Masters of camouflage, they use their coloration to avoid detection from both prey and predators. They can change color in as little as eight seconds to match their surroundings.

Banded Sole – A stripped fish, the Banded sole has periscoping eyes that can move independently and observe up to 180˚. They are difficult to find but make an excellent addition to the aquarium.


Flatfish are fairly easy to care for. It is important to make sure that they are provided with a soft, sandy substrate that they can lay against without injuring themselves. Avoid keeping them in tanks with significantly smaller fish as they are carnivorous and will eat anyone who looks like a meal. While Flounder may rise to mid-water to find food, Sole are solidly bottom dwelling, so sinking food is an absolute must. Water temperatures should be kept between 76-82˚ with a pH that is standard for reef aquariums.


Flatfish are carnivores, so a high-protein diet is essential in keeping your flatfish healthy. Fish, shrimp and crab meat are all excellent. Be sure that if you have Sole that the food sinks to the bottom of the tank so that they are encouraged to eat without having to leave their comfort zone.

Size: 18 Inches
Freshwater/ Saltwater: Saltwater
Diet: Carnivore
Reef Compatibility: 5
Tank Mate Compatibility: 6
Lifespan: Up to 10 Years

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