Got a photo? Identify fish instantly with the Fishby app.
Open the appDescription
The Giant Freshwater Stingray (Urogymnus polylepis) is one of the largest freshwater fish species in the world, characterized by its immense size, flattened disc-shaped body, and a long, whip-like tail armed with one or more venomous serrated spines. It is a benthic species, typically found buried in soft substrates of large tropical rivers.
Physical Characteristics
- Body shape
- flat
- Coloration
- Dorsal surface typically uniform grey to brownish-grey, sometimes with darker mottling or spots. Ventral surface is white to off-white. Juveniles may exhibit more distinct patterning.
- Scale type
- placoid
- Mouth position
- inferior
- Distinctive features
- Extremely large, flattened, circular to oval disc., Long, whip-like tail, often twice the length of the disc, bearing one or more large, venomous serrated spines near the base., Small, widely spaced eyes., Absence of dorsal fins., Skin covered in small, granular denticles (placoid scales), giving it a sandpaper-like texture. Larger, conical tubercles may be present on the disc and tail in some individuals.
- Dorsal fin
- Absent
- Tail fin
- Long, slender, whip-like, without caudal fin folds, but with one or more venomous spines.
- Pectoral fin
- Broad, forming the main disc of the body.
- Distinctive fins
- Pelvic fins are small and located at the base of the tail.
Identification Tips
Size
Its immense size (disc width up to 2.4 meters, total length over 5 meters) immediately distinguishes it from most other freshwater stingrays.
Tail
The extremely long, whip-like tail, often twice the disc length, with prominent venomous spines near the base, is a key identifier.
Coloration and Texture
Uniform grey to brownish-grey dorsal coloration and a rough, denticle-covered skin surface.
Absence of Dorsal Fins
Unlike some other ray species, U. polylepis lacks dorsal fins on its tail.
Habitat
- Water type
- freshwater
- Depth
- Typically found in shallow to moderate depths, often buried in soft substrates (sand, mud) of riverbeds. Can be found in depths up to 20 meters or more in larger river channels.
- Environment
- Large, slow-moving to moderately flowing tropical rivers, estuaries, and sometimes brackish water zones. Prefers areas with soft, sandy or muddy bottoms for burying. Found in main river channels, tributaries, and associated floodplains.
- Geographic range
- Primarily Southeast Asia, including the Mekong River basin (Cambodia, Laos, Thailand, Vietnam), Chao Phraya River (Thailand), and potentially other large river systems in Borneo (Kalimantan, Indonesia) and Peninsular Malaysia. Historical records suggest a wider range that has since diminished.
Aquarium Information
- Care level: expert
- Temperament: semi-aggressive
- Diet: carnivore
- Minimum tank size: Not suitable for home aquaria due to immense size and specialized needs. Requires public aquarium facilities with custom-built enclosures.
- Temperature: 24-28°C (75-82°F)
- pH level: 6.5-7.5
- Hardness: Soft to moderately hard (5-15 dGH)
- Compatibility: Only compatible with very large, robust fish that cannot be preyed upon and can tolerate similar water parameters. Best kept in species-specific exhibits.
- Special requirements: Requires extremely large, custom-built aquariums with vast open swimming areas and soft sand substrate for burying. Excellent filtration and water quality are paramount. Specialized diet of large live or frozen prey. Not recommended for private aquarists.
Wild Information
- Conservation status: endangered
- Seasonality: No distinct seasonal behavior patterns for breeding or migration are well-documented, though movements may be influenced by water levels and food availability during monsoon seasons.
- Market price: Not typically traded commercially for consumption due to conservation status and difficulty in handling. Occasionally targeted for illegal wildlife trade.
- Commercial importance: low
- Taste: Not commonly consumed due to conservation status and potential for venomous injury during capture and processing.
- Texture: Cartilaginous, similar to other rays.
- Nutritional value: Specific nutritional data is scarce due to limited consumption.
Key Facts
World's Largest Freshwater Fishrecord
The Giant Freshwater Stingray is considered one of the largest, if not the largest, freshwater fish species by weight and disc size, with individuals recorded exceeding 600 kg (1,300 lbs) and a disc width of 2.4 meters (7.9 feet).
Master of Camouflagebehavior
These stingrays are masters of camouflage, often burying themselves completely under a thin layer of sand or mud, making them incredibly difficult to spot in their natural habitat.
Powerful Venominteresting
Its tail is armed with one or more large, serrated spines capable of delivering a potent venom. These spines can be up to 38 cm (15 inches) long and are used purely for defense.
Long-Livedinteresting
While precise data is limited, it is believed that Giant Freshwater Stingrays can live for several decades in the wild, given their large size and slow growth rate.
Safety Information
Venomous- Safety level: venomous
- Venomous: Yes
- Edibility: not recommended
- Handling notes: Extreme caution is required when encountering or handling this species due to its large, potent venomous spines. The spines can inflict deep, painful wounds and deliver a potent venom that can cause severe pain, tissue necrosis, and in rare cases, systemic effects. Never approach or provoke a stingray. If stung, seek immediate medical attention. Anglers should cut the line if a stingray is caught, avoiding direct contact.
Similar Species
Mekong Smooth-back River Ray
Fluvitrygon kittipongi
Generally smaller, lacks the prominent denticles/tubercles on the disc, and has a smoother dorsal surface. Its tail is also typically shorter relative to its disc size.
Marbled Whipray
Fluvitrygon oxyrhynchus
Possesses a more pointed snout and distinct marbled or reticulated patterns on its dorsal surface, unlike the more uniform coloration of U. polylepis. Also generally smaller.
Leopard Whipray
Himantura leoparda
Primarily marine/estuarine, though can enter freshwaters. Distinguished by its distinctive leopard-like spot patterns and typically smaller size. Its tail often has alternating dark and light bands.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Chondrichthyes
- Order
- Myliobatiformes
- Family
- Urogymnidae
- Genus
- Urogymnus
- Species
- Urogymnus polylepis
Explore Giant Freshwater Stingray
Identify fish anywhere
Free on iOS, Android, and Web. Photo identification, full species details, and more.