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Short-finned Eel

Handle with care

Anguilla australis

Also known as: Southern Shortfin Eel, River Eel

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Description

The Short-finned Eel (Anguilla australis) is a catadromous fish species belonging to the family Anguillidae. It is characterized by its snake-like body, small, embedded scales, and a continuous dorsal, caudal, and anal fin. As its name suggests, it has a relatively short dorsal fin compared to its congener, the Long-finned Eel (Anguilla reinhardtii). This species undertakes extensive migrations between freshwater habitats for growth and marine environments for spawning.

Physical Characteristics

Body shape
eel-like
Coloration
Dorsal surface typically dark olive-green to brown, fading to a lighter, yellowish-white on the ventral side. Coloration can vary depending on habitat and age, with mature 'silver eels' becoming more silvery-grey prior to their spawning migration.
Scale type
cycloid
Mouth position
terminal
Distinctive features
Small, deeply embedded scales, giving the skin a smooth appearance., Continuous dorsal, caudal, and anal fins., Lower jaw slightly protruding beyond the upper jaw., Relatively short dorsal fin, originating well behind the pectoral fins and closer to the anus than to the gill opening., Pectoral fins are well-developed.
Dorsal fin
Originates well behind the pectoral fins, closer to the anus than to the gill opening. Continuous with the caudal and anal fins.
Tail fin
Rounded, continuous with dorsal and anal fins.
Pectoral fin
Well-developed and fan-shaped.
Distinctive fins
Absence of pelvic fins. The dorsal and anal fins are confluent with the caudal fin, forming a continuous fringe around the posterior part of the body.

Identification Tips

Dorsal Fin Origin

The most reliable distinguishing feature from the Long-finned Eel (Anguilla reinhardtii). In A. australis, the dorsal fin originates well behind the pectoral fins, closer to the anus than to the gill opening. In A. reinhardtii, it originates much closer to the gill opening.

Jaw Protrusion

The lower jaw typically protrudes slightly beyond the upper jaw.

Coloration

Generally dark olive-green to brown dorsally, with a lighter belly. Silvering occurs during maturation for spawning migration.

Pectoral Fins

Relatively broad and fan-shaped.

Habitat

Water type
freshwater
Depth
Typically found in shallow to moderate depths of freshwater systems, but migrates to deep oceanic waters for spawning.
Environment
Primarily found in rivers, streams, lakes, and estuaries. Prefers areas with abundant cover such as submerged logs, rocks, and dense aquatic vegetation. Tolerant of a wide range of water conditions, from clear mountain streams to turbid lowland rivers.
Geographic range
Native to southeastern Australia (including Tasmania), New Zealand, and some South Pacific islands (e.g., Norfolk Island, New Caledonia).

Aquarium Information

  • Care level: expert
  • Temperament: aggressive
  • Diet: carnivore
  • Minimum tank size: 750 gallons (2800 liters) for a single adult
  • Temperature: 60-75°F (15-24°C)
  • pH level: 6.5-8.0
  • Hardness: 5-20 dGH
  • Compatibility: Not suitable for community tanks due to predatory nature. Best kept alone or with very large, robust fish that cannot be swallowed.
  • Special requirements: Requires a very large, securely covered aquarium with excellent filtration. Eels are escape artists and will exploit any opening. Provide plenty of hiding places such as PVC pipes, caves, and dense vegetation. A substrate of sand or fine gravel is preferred for burrowing. Mimic natural riverine conditions with good water flow.

Wild Information

  • Conservation status: least concern
  • Seasonality: Adult eels migrate to sea for spawning during autumn and winter. Juveniles (glass eels) return to freshwater in spring and summer.
  • Market price: Varies significantly by region and demand, often sold for consumption.
  • Commercial importance: medium
  • Taste: Rich, oily, and distinctively savory.
  • Texture: Firm, flaky, and somewhat gelatinous.
  • Cooking methods: smoked, grilled, fried, stewed, jellied
  • Nutritional value: High in protein, Omega-3 fatty acids, and vitamins A, D, and E.

Key Facts

Catadromous Life Cyclebehavior

Short-finned Eels are catadromous, meaning they live in freshwater and migrate to the sea to spawn. Their exact spawning grounds are still largely unknown but are believed to be in deep oceanic waters of the Coral Sea or Tasman Sea.

Incredible Migrationamazing

After hatching, larval eels (leptocephali) drift on ocean currents for months or even years before transforming into glass eels and migrating back into freshwater estuaries and rivers.

Longevityinteresting

Short-finned Eels can live for many years in freshwater, with some individuals recorded living over 20 years before undertaking their single spawning migration.

No Pelvic Finsevolution

Like all true eels (order Anguilliformes), Short-finned Eels lack pelvic fins, which are present in most other fish.

Safety Information

Handle with care
  • Safety level: caution
  • Venomous: No
  • Edibility: edible
  • Handling notes: Eels are extremely slippery and powerful. Handle with care to avoid injury to both the handler and the fish. Their bite can be painful due to numerous small, sharp teeth. Use a wet cloth or gloves for grip if necessary. Always return unwanted eels to the water quickly and gently.

Similar Species

Long-finned Eel

Anguilla reinhardtii

The dorsal fin of Anguilla reinhardtii originates much further forward, closer to the gill opening than to the anus. It also typically grows larger and has a more mottled or marbled coloration.

New Zealand Longfin Eel

Anguilla dieffenbachii

Found only in New Zealand. Its dorsal fin also originates further forward than A. australis, and it can reach much larger sizes. The pectoral fin is also typically longer than the head in A. dieffenbachii, whereas it is shorter than the head in A. australis.

Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Anguilliformes
Family
Anguillidae
Genus
Anguilla
Species
Anguilla australis

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