Freshwater Moray

Gymnothorax polyuranodon
Freshwater Moray - Marinewise © 2025 MarineWise

Quick Facts

Scientific name Gymnothorax polyuranodon
Other names Blackspotted Moray, Manytoothed Moray, Spotted Freshwater Moray
Size Up to 1.2 m (4 ft
Weight Under 5 kg (11 lb)

Distribution

Habitat & AU Distribution Fresh & brackish waters in creeks & streams near rocks & boulders of deeper pools - marine larvae
Depth Range 0 - 10 m (33 ft)
Freshwater Moray Distribution

Interesting Info

  • The Freshwater Moray is one of the few moray eels that regularly ventures into freshwater rivers and streams, though it also lives in estuaries and coastal waters.
  • In Australia, it is recorded mainly from Queensland, the Northern Territory, and occasionally northern WA, often in tidal rivers and coastal creeks.
  • They are long and muscular with a cream to yellowish body covered in dark brown blotches or spots, giving them excellent camouflage among rocks and roots.
  • They are opportunistic predators, feeding on fish, crabs, shrimp, and other crustaceans. Their sharp teeth and powerful jaws make them formidable hunters.
  • Like all morays, they breathe by constantly opening and closing their mouths to pump water over their gills — a behaviour that looks threatening but isn’t aggression.
  • They are typically found in shallow, rocky or root-filled pools of rivers and creeks, often hiding in holes or under logs during the day and hunting at night.
  • The Freshwater Moray is euryhaline, meaning it can tolerate a wide range of salinities — from the fully marine ocean, to brackish estuaries, all the way into freshwater rivers and pools.
  • Scientists think they migrate into rivers to feed and grow, then return to the sea to spawn, similar to eels (Anguillidae). This makes them an important species for understanding diadromous life cycles — fish that move between saltwater and freshwater at different life stages.
  • Breeding is believed to take place in marine waters, with larvae (called leptocephali) drifting in the ocean before juveniles migrate into estuaries and rivers. This means freshwater populations depend on connections to the sea.
  • Lifespan is not well studied, but morays in general can live 10–15 years or more in the wild.
Species Interaction

Recreational Fishing & Aquariums

Freshwater moray eels are not commonly targeted by recreational anglers, but are by certain communities that consider them a delicacy. In addition, some people find freshwater moray eels fascinating and rewarding to keep in their aquariums due to their unique appearance and interesting behaviours.

Scientific Classification

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Anguilliformes

Family: Muraenidae

Genus: Gymnothorax

Species: Gymnothorax polyuranodon

Conservation Status

The conservation status of the freshwater moray is currently listed as “Data Deficient” on the International Union for Conservation of Nature (IUCN) Red List. This means that there is insufficient information available about the population and distribution of the species to determine its conservation status.

Fish Taste Quality

Freshwater moray are not widely consumed in Australia. They are considered a delicacy in some Asian and Pacific Island countries.

Taste Rating: 3/5

How to catch
Freshwater Moray

Catch Difficulty: Intermediate

Tackle: Running Sinker Rig, Artificial Rig

Bait: Fresh cut flesh baits, Lures, Prawns, Worms, Yabbies, Live minnow, Insects

Technique: Keep bait on the bottom, Keep bait close to structure

Popularity: Not targeted - Bycatch

Freshwater Moray
As Aquarium Fish

Care Level: Moderate to difficult

Temperament: Very Aggressive

Diet: Carnivore

Reef Compatible: No

Minimum Tank Size: 250+ gallons