Cynoglossus cynoglossus, commonly known as the Bengal tonguesole, sometimes called the Gangetic tongue sole, is a species of tonguefish. It is commonly found in the Indian Ocean, particularly in brackish water and muddy or sandy bottoms off the coast of India, Bangladesh and Burma east to the Philippines.

It reaches a length between 12.5 cm and 20 cm. The dorsal soft rays number between 95 and 102, and the anal soft rays between 72 and 78. It feeds on benthic invertebrates.

DESCRIPTION:

Cynoglossus cynoglossus typically exhibits the typical flatfish body shape, with both eyes situated on one side of the head. They have a laterally compressed body, which is oval in shape and covered in small, rough scales. The coloration of the upper side of the fish varies depending on the substrate, ranging from light brown to dark green or olive, often with darker blotches or spots. The underside is typically white or pale.

PHYSICAL CHARACTERISTICS:

LENGTH:

Adults of Cynoglossus cynoglossus can reach lengths of up to 40 centimeters (about 16 inches), although they are commonly found at smaller sizes.

WEIGHT:

The weight of these fish varies depending on age and environmental factors.

EYES:

 Both eyes are positioned on the right side of the body, while the left side is typically pigmented to match the substrate, helping the fish blend into its surroundings.

MOUTH:

 The mouth is large and terminal, with small conical teeth adapted for feeding on small fish, crustaceans, and benthic invertebrates.

MORPHOLOGY:

Cynoglossus cynoglossus exhibits a distinctive morphological adaptation common to flatfish species known as asymmetry. As larvae, they have a bilaterally symmetrical body, but as they grow, one eye migrates to the opposite side of the head, resulting in a flatfish with both eyes located on one side. This adaptation allows them to lie flat on the ocean floor, camouflaging themselves against predators and prey alike.

REPRODUCTION:

The reproductive behavior of Cynoglossus cynoglossus involves spawning, where females release eggs into the water column, which are then fertilized externally by the males. Fertilized eggs hatch into larvae, which undergo metamorphosis as they develop into juveniles and eventually adults. The exact details of their reproductive biology, including spawning seasons and spawning grounds, may vary depending on their geographic location.

HABITAT:

Cynoglossus cynoglossus is typically found in shallow coastal waters, particularly in areas with sandy or muddy substrates. They are often associated with estuaries, lagoons, and intertidal zones, where they can bury themselves in the sediment to avoid predators and ambush prey. These fish are commonly encountered at depths ranging from a few meters to around 50 meters (approximately 164 feet).

UNIQUE FEATURES:

CAMOUFLAGE: One of the most remarkable features of Cynoglossus cynoglossus is its ability to camouflage itself against the ocean floor. The pigmentation on the underside of the fish matches the color and pattern of the surrounding substrate, making them virtually invisible to both predators and prey when lying motionless on the seabed.

ADAPTATIONS FOR AMBUSH PREDATION: With their flattened bodies and upward-facing eyes, Tiger Tongue Sole are well-suited for ambush predation. They lie partially buried in the sediment, waiting for unsuspecting prey to swim within striking distance before quickly lunging forward to capture their meal.

OMNIVOROUS DIET: While Cynoglossus cynoglossus primarily feeds on small fish, crustaceans, and benthic invertebrates, they are opportunistic feeders and may consume a variety of prey items found within their habitat, including detritus and plant matter.

COMMERCIAL IMPORTANCE: These fish are of commercial importance in some regions, where they are harvested for human consumption. They are often targeted by commercial and artisanal fisheries using bottom trawls, gillnets, and other fishing gear. Additionally, they may also be caught incidentally as bycatch in fisheries targeting other species.