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Tonguefish

Freshwater Sole ~ Flounder Family: Soleidae

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Brachirus panoides Photo © Animal-World: Courtesy Ken Childs

   The tail on the Tongue fish, also known as the Freshwater Sole or Flounder, is fused with the rest of the fins which gives it the tongue-like shape!

   The Freshwater Sole pictured here is a freshwater member of a family that occurs worldwide. Most sole fish species of live in the ocean but a few smaller ones live in fresh or brackish water. These are an interesting species that will do quite well in an aquarium if given the correct environment. The intriguing anatomy of sole fish is that they are flattened, or compressed laterally, and they swim on their side on the bottom of their environment. One of their eyes migrates to the side which points up, leaving the other side or 'bottom' side blind, making for a very unique looking fish.

   Sole fish are also referred to as flounder fish, and because of their flat and somewhat rounded 'tongue-like' appearance, they are also called Tonguefish. Beyond these designations, the additional names of Pan Sole and Hogchoker Sole are used for the three species that are occasionally imported. The species discussed here Brachirus panoides, which comes from Southeast Asia, and Brachirus pan, imported from Bangladesh and India, are both referred to as Pan Soles. The third species Trinectes maculatus, which originates in North America, is called the Hogchoker Sole.

For more Information on keeping this fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:
   This Freshwater Sole, also called the Flounder, Tonguefish and Pan Sole, was described by Cuvier in 1829. They are found in Southeast Asia from Thailand to Indonesia, dwelling on the bottoms of estuaries and in the lower courses of rivers.

Status:
   The species is not listed on the IUCN Red List.

Description:
   The body of this Freshwater Sole is a rich orangish brown mottled with black spots and blotches. They are compressed laterally and they swim on one side on the bottom of their environment. One of the eyes migrates to the side which points up, leaving the other side or 'bottom' side blind. Their anal fins are fused with the other fins, edging their entire body, thus giving them a 'tongue' like appearance.

Size - Weight:
   These fish can get up to 8 inches (20cm) long.

Care and feeding:
   Since they are carnivores, the Tonguefish, Freshwater Sole, or Flounder will eat all types of protein foods. They should be fed a diet of live or fresh frozen foods such as brine shrimp, black worms, earthworms or bloodworms. They are not aggressive feeders so food may have to be poured directly on top of them to make sure they get enough to eat. They will also eat tiny fish so make sure any tank mates are too large to be able to fit into their mouths.
   The Tonguefish is sometimes found in the mouths of rivers where they dump into the ocean so they will do well in either fresh or brackish water tanks. They spend virtually all of their time on the bottom so special care needs to be given to where they live. To feel secure, they should be able to bury themselves which means that very fine gravel or sand is the substrate of choice. It is not unusual to see only a pair of eyes poking up through the sand.

Water Region: Top, Middle, Bottom:
   They will spend most of their time directly on the bottom although they may occasionally stick to the sides of the tank.

Acceptable Water Conditions:
   Ph: 7.0 to 8.0
   Temp: 74 - 82° F (23 - 28° C)

Social Behaviors:
   They are not aggressive but they may eat small fish so make sure any tank mates are too large to be able to fit into their mouths. The other concern of keeping them in a community tank is making sure they get enough food as they are not aggressive eaters.

Sexual Differences:
   Unknown.

Breeding/Reproduction:
   Has not been bred in captivity. In their native environment they are pelagic spawners and the eggs are non-adhesive.

Availability:
   Although commonly available, the Tonguefish is not a fish that many stores will carry on a regular basis. It is definitely a candidate for a special order.

Author: Ken Childs
Additional Information: Clarice Brough, CFS

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Latest Comments
They can be aggresive and will also eat small fish. Anonymous 2007-04-13
There are extremely aggressive. Jack 2006-03-18

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