TankBud

Freshwater moray eel

Gymnothorax polyuranodon

Also known as Freshwater tiger moray, Many-toothed moray

FreshwaterBrackishFish

Freshwater moray eel (Gymnothorax polyuranodon)
The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature
73–82°F
23–28°C
pH
7.0–8.2
Adult size
35.4 in
90 cm
Minimum tank
159 gal
600 L
Temperament
Aggressive
Social behavior
Solitary
Tankmates
With caution
Swim level
Bottom
Diet
Carnivore
Difficulty
Difficult
Breeding
No record
Rarity
Rare
Family
Muraenidae
Origin
Rivers of the Indo-Pacific islands, from Sri Lanka to Fiji

Overview

The freshwater moray eel is a true moray that lives in fresh and brackish rivers, a large, aggressive predator for a dedicated system only. It suits only experienced keepers.

Did you know

Most freshwater morays in shops are really estuary fish that only tolerate fresh water for a while. This species is the honest article, able to spend years in genuinely fresh river water far from the sea.

Caring for the freshwater moray eel

Give a freshwater moray eel a large tank of at least 159 gal (600 L), with secure rockwork and caves. It hides among the rock by day and hunts at night. Use a sand or fine gravel bed and dim light. It is a determined escape artist, so a heavy, sealed lid is not optional.

Keep it in hard, alkaline water at 73 to 82°F (23 to 28°C) and a pH of 7.0 to 8.2. Many keepers add some marine salt. Feed meaty foods such as strips of fish, prawn and other seafood on a stick, which keeps your fingers clear.

The freshwater moray eel is an aggressive predator, and it is best kept on its own. It will eat any tank mate small enough to swallow, so choose any companions with great caution.

It is catadromous, migrating to the sea to spawn. Its young drift as transparent leptocephalus larvae before entering rivers, so it is effectively not bred in home aquaria.

Good to know

The freshwater moray eel belongs to the moray family, Muraenidae, and is boldly marked with dark leopard spotting. It is one of the larger freshwater fishes of its region, and exceptional wild fish are recorded to about 150 cm. It is also called the freshwater tiger moray or many-toothed moray.

In the wild

The freshwater moray eel ranges across the islands of the Indo-Pacific, from Sri Lanka to Fiji. It lives in rivers, usually within a short distance of the coast.

Common questions

What size tank does a freshwater moray eel need?

A freshwater moray eel needs at least 159 gal (600 L). It spends most of its time in the bottom.

What temperature and pH does a freshwater moray eel need?

A freshwater moray eel is comfortable at 73–82°F (23–28°C) with a pH of 7.0–8.2.

What does a freshwater moray eel eat?

A freshwater moray eel eats meaty foods such as strips of fish, prawn and other seafood. Feed it on a stick to keep your fingers clear.

How big does a freshwater moray eel get?

An adult freshwater moray eel reaches about 35.4 in (90 cm).

How does a freshwater moray eel breed?

A freshwater moray eel migrates to the sea to spawn, and its young drift there as transparent leptocephalus larvae before entering rivers. It is effectively not bred in home aquaria.

Related species