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Strongylura strongylura, commonly known as the Needlefish or Spottail Needlefish, is a slender, elongated fish characterized by its distinctive long, needle-like jaws. It is a predatory species found in brackish and freshwater environments, primarily in estuaries, rivers, and coastal areas of the Indo-Pacific region. Its streamlined body and dorsal and anal fins positioned far back on the body are adaptations for swift, darting movements to ambush prey. This species is known for its ability to leap out of the water, especially when startled or pursuing prey.
Physical Characteristics
- Body shape
- elongated
- Coloration
- Dorsal surface is typically greenish to bluish-grey, fading to silvery-white on the flanks and belly. A prominent dark lateral stripe may be present along the sides. The caudal fin often has a distinct dark spot, especially in juveniles and subadults, which gives rise to the common name 'Spottail Needlefish'.
- Scale type
- cycloid
- Mouth position
- terminal
- Distinctive features
- Extremely elongated, slender body, Long, needle-like jaws with numerous sharp teeth, Dorsal and anal fins positioned far back on the body, nearly opposite each other, Often a dark spot on the caudal fin (tail fin)
- Dorsal fin
- Single dorsal fin, typically with 13-17 soft rays, positioned posteriorly, opposite the anal fin.
- Tail fin
- Caudal fin is truncate to slightly emarginate, often with a dark spot at its base or on the lower lobe.
- Pectoral fin
- Small, located low on the body, typically with 10-12 rays.
- Distinctive fins
- Pelvic fins are small and abdominal, located far back on the belly. All fins lack spines.
Identification Tips
Body Shape
Look for the extremely slender, elongated, almost cylindrical body, characteristic of all needlefish.
Jaws
Observe the very long, pointed jaws, resembling a needle or beak, filled with numerous small, sharp teeth.
Fin Placement
Note the dorsal and anal fins are set far back on the body, almost directly opposite each other, close to the caudal fin.
Caudal Fin Spot
In Strongylura strongylura specifically, look for a distinct dark spot on the caudal fin, especially noticeable in younger individuals.
Coloration
The greenish-grey dorsal and silvery-white ventral coloration, often with a lateral stripe, is typical.
Habitat
- Water type
- brackish
- Depth
- Typically found in shallow waters, from the surface down to a few meters.
- Environment
- Estuaries, coastal lagoons, mangrove areas, lower reaches of rivers, and occasionally in fully marine coastal waters. Prefers areas with submerged vegetation or structures for ambush predation.
- Geographic range
- Indo-West Pacific region, ranging from East Africa and Madagascar eastward to the Philippines, and northward to southern Japan, southward to Australia. Also found in various island nations within this range.
Aquarium Information
- Care level: advanced
- Temperament: aggressive
- Diet: carnivore
- Minimum tank size: 250 gallons
- Temperature: 24-28°C (75-82°F)
- pH level: 7.0-8.0
- Hardness: 10-20 dGH
- Compatibility: Best kept in a species-specific tank or with very large, robust, and fast-moving fish that cannot be swallowed. Avoid small or slow-moving tank mates.
- Special requirements: Requires a very large tank with ample swimming space and a tight-fitting lid due to its jumping ability. A diet of live or frozen whole fish (e.g., silversides, krill) is essential. Good filtration and stable water parameters are crucial. Can be sensitive to poor water quality.
Wild Information
- Conservation status: least concern
- Seasonality: Present year-round in its native range, with potential seasonal variations in abundance or distribution influenced by breeding cycles and prey availability.
- Market price: Low
- Commercial importance: low
- Taste: Mild, slightly sweet
- Texture: Firm, flaky
- Cooking methods: Frying, Grilling, Baking, Steaming
- Nutritional value: Good source of lean protein and omega-3 fatty acids. Contains numerous small bones which can be challenging for consumption.
Key Facts
Jumping Predatorsbehavior
Needlefish are renowned for their ability to leap out of the water, often to escape predators or to catch flying insects, but sometimes seemingly without provocation, posing a hazard to people.
Ambush Huntersbehavior
Their streamlined body and posterior fin placement allow them to accelerate rapidly from a stationary position, making them effective ambush predators of smaller fish and crustaceans.
Green Bonesinteresting
Like many other species in the Belonidae family, the bones of Strongylura strongylura can sometimes appear green due to the presence of biliverdin, a bile pigment. This is harmless and does not affect edibility.
Estuarine Specialistsinteresting
Strongylura strongylura is highly adapted to life in brackish water environments, tolerating a wide range of salinities from freshwater rivers to coastal marine areas.
Safety Information
Handle with care- Safety level: caution
- Venomous: No
- Edibility: edible
- Handling notes: Needlefish have sharp teeth and can inflict painful bites if handled carelessly. Their elongated, pointed jaws can also cause puncture wounds. More significantly, their tendency to leap out of the water at high speeds, especially when startled by lights at night, poses a risk of injury to humans in boats or on docks. There have been documented cases of needlefish jumping and impaling people. Handle with extreme care, preferably using a net or gloves, and be aware of their jumping behavior, especially at night.
Similar Species
Flat-tailed Needlefish
Strongylura leiura
S. leiura typically has a more compressed (flatter) caudal peduncle and lacks the prominent dark spot on the caudal fin that is characteristic of S. strongylura. Its jaws may also be slightly shorter in proportion to its body length.
Houndfish
Tylosurus crocodilus
The Houndfish is generally much larger and more robust than S. strongylura. It has a more pronounced, often greenish-blue dorsal coloration and lacks the distinct caudal fin spot. Its jaws are also very long but typically thicker and more powerful.
Freshwater Garfish
Zenarchopterus dispar
While also elongated with needle-like jaws, Zenarchopterus species (halfbeaks) have a significantly shorter upper jaw compared to the lower jaw, especially in juveniles, which is a key distinguishing feature from Strongylura species where both jaws are equally elongated.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Actinopterygii
- Order
- Beloniformes
- Family
- Belonidae
- Genus
- Strongylura
- Species
- strongylura
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