FRESHWATER RIVER SOLE (Brachirus panoides)

• Aquarist Experience Level: Advanced
• Size of fish - inches: 7.9 inches (20.07 cm)
• Minimum Tank Size: 55 gal (208 L)
• Temperament: Peaceful
• Aquarium Hardiness: Moderately hardy
• Temperature: 74.0 to 82.0° F (23.3 to 27.8° C)

The Freshwater Sole Brachirus panoides was described by Cuvier in 1829. They are found in Southeast Asia from Thailand to Indonesia. The species is not listed on the IUCN Red List. However there is some concern about population declines caused by dragger nets, but not to the point of actually causing a severe decrease in population.

Other common names B. panoides are known by are False Freshwater Sole, False Pan Sole, and Tonguefish. The additional names of Pan Sole and Hogchoker Sole are used for this fish, as well as two other species that are occasionally imported. The species Brachirus pan, imported from Bangladesh and India, Is referred to as True Pan Sole and Pan Sole. The species, Trinectes maculatus, an American Sole which originates in North America, is called the Hogchoker Sole. The T. maculatus is very similar to the False Freshwater Sole in overall appearance, but these two can be told apart by their body shape and tail.

False Pan Sole are seen on the bottom of estuaries and in the lower courses of rivers. These fish tend to live in pure freshwater as well as brackish water. They will normally stay covered with sand or mud most of the day and hunt at night. Soles camouflaged themselves in a combination of colors that match their surroundings, making them very hard to spot. They will feed on benthic invertebrates in nature.

True Soles - Family Soleidae
The True Soles live in fresh water and saltwater environments. They have a similar body shape to the Tonguefish, but are often more rounded, and they have a small rounded head. The dorsal fin starts above or before eyes. Both dorsal and anal fins extends back to the caudal fin, and can be fused with it or not. They may or may not have pectoral fins, and there are no fin spines.

True Soles begin life with an eye on each side of the head. But during development the left eye moves around onto the right side of the head. They lie on on their left side ("blind" side) on the bottom of their environment, usually buried in mud.

https://animal-world.com/encyclo/fresh/miscellaneous/Tonguefish.php