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Cynoglossus arel, commonly known as the Tongue Sole, is a species of flatfish belonging to the family Cynoglossidae. Like other members of its family, it is characterized by its elongated, tongue-shaped body and the migration of one eye to the other side of the head during development, resulting in both eyes being on the same side (typically the left side in this species). It is a demersal fish, inhabiting soft bottoms in coastal and estuarine environments.
Physical Characteristics
- Body shape
- flat
- Coloration
- Dorsal side typically brownish to grayish, often with irregular darker blotches or spots, providing camouflage against the seabed. Ventral side (blind side) is whitish.
- Scale type
- ctenoid
- Mouth position
- inferior
- Distinctive features
- Elongated, tongue-shaped body, tapering to a pointed tail., Both eyes are on the left side of the head, with the upper eye slightly in advance of the lower eye., Small, inferior mouth, curved and asymmetrical., No pectoral fins., Dorsal and anal fins confluent with the caudal fin., Lateral line present on both eyed and blind sides, with an accessory lateral line on the eyed side.
- Dorsal fin
- Long, continuous, originating near the snout and confluent with the caudal fin. Typically 116-130 rays.
- Tail fin
- Pointed, confluent with dorsal and anal fins.
- Pectoral fin
- Absent.
- Distinctive fins
- Anal fin long, continuous, originating behind the gill opening and confluent with the caudal fin. Typically 90-106 rays. Pelvic fins are small, asymmetrical, and located on the blind side.
Identification Tips
Body Shape
Look for the distinctive elongated, tongue-like body that tapers to a point.
Eye Placement
Confirm both eyes are on the left side of the head, with the upper eye slightly anterior to the lower.
Fin Absence
Note the complete absence of pectoral fins, a key characteristic of the family Cynoglossidae.
Lateral Lines
Observe the presence of two lateral lines on the eyed side (one main, one accessory) and one on the blind side.
Mouth
Identify the small, inferior, and asymmetrical mouth.
Habitat
- Water type
- saltwater
- Depth
- Typically found in shallow coastal waters, estuaries, and brackish lagoons, ranging from 10 to 100 meters, but most commonly in less than 50 meters.
- Environment
- Demersal, inhabiting soft muddy or sandy bottoms. Often buries itself in the substrate, leaving only its eyes exposed.
- Geographic range
- Indo-West Pacific: Red Sea and East Africa to the Philippines, north to southern Japan, and south to northern Australia. Common in the Arabian Sea, Bay of Bengal, and Southeast Asian waters.
Aquarium Information
- Care level: expert
- Temperament: peaceful
- Diet: carnivore
- Minimum tank size: Not typically kept in home aquariums due to size and specialized needs. Requires very large, species-specific setups for public aquaria.
- Temperature: 24-28°C (75-82°F)
- pH level: 7.8-8.4
- Hardness: 1.020-1.025 SG
- Compatibility: Not suitable for typical community aquariums. Best kept in species-specific exhibits or with very large, non-aggressive bottom dwellers in public aquaria.
- Special requirements: Requires a large tank with a deep, soft sand substrate for burrowing. Excellent water quality and strong filtration are essential. Not recommended for hobbyists.
Wild Information
- Conservation status: least concern
- Seasonality: Availability can vary regionally, often caught year-round with peak seasons depending on local spawning patterns and fishing regulations.
- Market price: Varies significantly by region and market demand, often considered a high-value food fish.
- Commercial importance: high
- Taste: Mild, delicate, slightly sweet
- Texture: Fine, firm, flaky white flesh
- Cooking methods: Pan-frying, Steaming, Grilling, Baking, Poaching
- Nutritional value: Good source of lean protein, low in fat, contains Omega-3 fatty acids, vitamins (B12, D), and minerals (selenium, phosphorus).
Key Facts
Master of Camouflagebehavior
Tongue soles are masters of camouflage, able to change their coloration to blend seamlessly with the sandy or muddy seabed, making them incredibly difficult to spot by predators and prey alike.
Unique Eye Migrationevolution
During their larval stage, one eye of the tongue sole migrates across the top of its head to join the other eye on the left side, a remarkable adaptation for their bottom-dwelling lifestyle.
No Pectoral Finsinteresting
Unlike many other fish, Cynoglossus arel completely lacks pectoral fins, relying on its dorsal and anal fins for propulsion and maneuvering along the seabed.
Burrowing Behaviorbehavior
These fish frequently bury themselves in soft substrates, often leaving only their eyes exposed, to ambush prey or hide from predators.
Safety Information
Safe- Safety level: safe
- Venomous: No
- Edibility: edible
- Handling notes: No specific handling precautions are required beyond standard fish handling practices. They do not possess venomous spines or other harmful defenses. Handle carefully to avoid damaging their delicate skin and fins.
Similar Species
Large-eyed Tongue Sole
Cynoglossus macrostomus
C. macrostomus generally has larger eyes and a slightly different count of dorsal and anal fin rays. C. arel typically has a more pointed snout and a higher number of scales in the lateral line.
Bengal Tongue Sole
Cynoglossus lingua
C. lingua tends to have a more elongated body and a higher number of dorsal and anal fin rays (D: 130-140, A: 100-115) compared to C. arel (D: 116-130, A: 90-106). The snout shape can also differ subtly.
Malabar Sole
Cynoglossus semifasciatus
C. semifasciatus is generally smaller and has distinct dark cross-bands on its body, which are typically absent or much less pronounced in C. arel.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Actinopterygii
- Order
- Pleuronectiformes
- Family
- Cynoglossidae
- Genus
- Cynoglossus
- Species
- Cynoglossus arel
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