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Marbled swamp eel

Synbranchus marmoratus

Also known as Muzzled swamp eel

FreshwaterFish

Marbled swamp eel (Synbranchus marmoratus)

Care at a glance

Temperature
72–82°F
22–28°C
pH
6.0–7.8
Adult size
39.4 in
100 cm
Minimum tank
119 gal
450 L
Temperament
Aggressive
Social behavior
Solitary
Tankmates
With caution
Swim level
Bottom
Diet
Carnivore
Difficulty
Difficult
Breeding
No record
Rarity
Rare
Family
Synbranchidae
Origin
Central and South American wetlands

Overview

The marbled swamp eel is a large, strong, air-breathing eel for a big, securely covered tank. It is aggressive and solitary, and only experienced keepers should take it on.

Did you know

When its water dries up, the marbled swamp eel can burrow into mud and estivate for months. It lives off its own body reserves until the rains return. A drought that would kill most fish just puts this one on pause.

Caring for the marbled swamp eel

Give the marbled swamp eel a long, heavily built tank of at least 119 gal (450 L). That is a realistic minimum for a fish approaching a meter. It is a determined escape artist that can climb out and even cross damp ground, so fit a lid that seals completely.

It lives on the bottom and needs a soft substrate to rest in, with sturdy hiding places such as pipes and caves. It is adaptable over 72 to 82°F (22 to 28°C) and a pH of 6.0 to 7.8. It gulps air at the surface, so it copes with low oxygen and does not need pristine flow.

Feed meaty foods such as earthworms, prawn and pieces of fish. It is aggressive and will attack or eat tank mates, so keep it alone or add companions only with real caution. Almost anything small enough to swallow will be eaten, and it can injure fish its own size.

It is not bred in home aquariums, so captive spawning is essentially unrecorded. In the wild, it is known to tend a nest.

Good to know

Synbranchus marmoratus belongs to Synbranchidae, the swamp eels. It breathes air through the lining of its gut and mouth, which lets it survive foul water and short trips overland.

In the wild

The marbled swamp eel ranges across the wetlands of Central and South America, from Mexico to northern Argentina. It lives in swamps, ditches, canals and slow streams that often run low on oxygen.

Common questions

What size tank does a marbled swamp eel need?

A marbled swamp eel needs at least 119 gal (450 L). It spends most of its time in the bottom.

What temperature and pH does a marbled swamp eel need?

A marbled swamp eel is comfortable at 72–82°F (22–28°C) with a pH of 6.0–7.8.

What does a marbled swamp eel eat?

A marbled swamp eel eats meaty foods, such as earthworms, prawn and pieces of fish. It will also eat almost any tank mate small enough to swallow.

How big does a marbled swamp eel get?

An adult marbled swamp eel reaches about 39.4 in (100 cm).

How does a marbled swamp eel breed?

Marbled swamp eels are not bred in home aquariums, so captive spawning is essentially unrecorded. In the wild, they are known to tend a nest.

Related species