Not furry, but we like them anyway.

Fire Eel

Mastacembelus erythrotaenia

Also called Fire spiny eel

SpeciesShort profile

From Lowland Southeast Asia, including Thailand, Cambodia, Laos, Vietnam, Peninsular Malaysia, Borneo and Sumatra, in slow rivers and seasonally flooded plains with muddy bottoms.1 2 3

At a glance the quick version

Length100 cm1 2 3

Sizelarge

Maximum about 1 m, the largest member of the spiny eel family.

Vivid red markings

Largest spiny eel

Calm with big tankmates

2 3

Looks how to spot one

Long, slightly flattened eel-like body with small spines along the back

A dark grey to brown body with a lighter belly, decorated with bright red stripes on the head and front half and red spots and dashes further back. The markings are yellow to amber in young fish and deepen to red with age, and the fins are often edged in red.1 2

Coloursblackdark greybrownredamber1 2

Personality what they are like

Usually peaceful, but it is a predator that may eat fish small enough to swallow, so tankmates should be clearly too big to be prey.3

Daily activity how busy a day looks

A bottom dweller that spends a lot of time buried in the substrate with just its snout showing, coming out to forage.2 3

Grooming and care the hands-on bits

Soft sand is essential so it can bury itself. Seriously Fish rates it moderate in difficulty (5 of 8).3

Home where they are happiest

A large tropical tank; Seriously Fish suggests a base of at least 120 x 60 cm (about 430 L), 24-28 °C, pH 6.0-7.0 and 5-12 dGH. FishBase gives 24-28 °C and pH 6.0-8.0.3 1

Food basics what goes in the bowl

In the wild it eats insect larvae, worms, small fish and some plant matter. In aquariums it prefers meaty foods such as prawn, krill and lancefish, and rarely eats plants.1 2 3

Company who they like around

Usually kept alone, as it can be testy with its own kind. Groups of five or more can work in a very large tank.3

The story where it all began

Pieter Bleeker described the fire eel in 1850. It is fished for food in its home countries and has become a showpiece fish for large aquariums thanks to its fiery markings.1 2 3

Fun facts for the dinner table

1
It is the largest species in the spiny eel family, reaching around 1 m.2
2
Young fire eels have yellow or amber markings that turn deep red as they mature.2
3
It has occasionally been bred by accident in home aquariums.3
4
In the wild it is often caught by pumping dry small pools where it hides.1

Recognised by the official bits

FishBase: Described by Bleeker in 1850; family Mastacembelidae (spiny eels).1
IUCN Red List (via FishBase): Least Concern (assessed 2019).1

The care rhythm a typical week and year

A typical home-care rhythm for a Fire Eel. A starting point, not a vet's advice.

Feedingevery day
Water changeAbout 30 to 50% of the waterevery week
Water testevery week
Filter rinseevery 2 weeks

Owner questions the things everyone asks

How often should I feed my Fire Eel?

Feed your Fire Eel once a day, as Furry Diary's starting plan suggests. Offer only as much as it can eat in a few minutes to avoid overfeeding. Pet Wiki plan

What does a Fire Eel eat, and what should it never eat?

Fire Eels enjoy meaty foods like prawn, krill, and lancefish. They rarely eat plants, so avoid feeding them any plant-based foods or anything that could be too large to swallow.1 2 3

How much space does a Fire Eel need?

A Fire Eel needs a large tank, with Seriously Fish recommending a base of at least 120 x 60 cm (about 430 liters). This gives it room to bury itself and forage.3

What temperature, light or water does a Fire Eel need?

Keep the water temperature between 24-28 °C, with a pH of 6.0-7.0 and hardness of 5-12 dGH. Soft sand is essential for it to bury itself, and moderate lighting is fine.3 1

How often should I clean a Fire Eel's home?

Furry Diary's plan suggests a weekly water change of about 30-50%, along with a weekly water test and a filter rinse every two weeks. This keeps the water quality stable. Pet Wiki plan

Can a Fire Eel live with others?

Fire Eels are usually peaceful but may eat small fish that fit in their mouth. They are often kept alone, though a group of five or more can work in a very large tank.3

How long does a Fire Eel live?

The lifespan of a Fire Eel varies, so ask a good breeder or exotic-pet vet for specific details. With proper care, they can live many years.

Can I handle a Fire Eel?

Handling a Fire Eel is not recommended as it can stress the fish and damage its delicate body. It's best to observe it from outside the tank.2 3

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

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Where this comes from

Every fact on this page has a numbered source. Spotted an error? [email protected].

Mastacembelus erythrotaenia, Fire eel - FishBase fishbase.seused for origin, taxonomy, IUCN status, size, colour, water parameters, diet, fun facts
Fire eel - Wikipedia en.wikipedia.orgused for distribution, size, appearance, behaviour, diet, fun facts
Mastacembelus erythrotaenia - Seriously Fish seriouslyfish.comused for tank size, water parameters, substrate, diet, compatibility, group keeping, fun facts

Checked 2026-09-30. Text is written in our own words from these sources.