Golden Fire Eel - Mastacembelus erythrotaenia

Golden Fire Eel (Mastacembelus erythrotaenia)

The Golden Fire Eel is a spectacular large freshwater spiny eel admired for its elongated body, rich golden to orange-red markings and secretive bottom-dwelling behaviour. This colour form of the Fire Eel is best suited to very large mature aquariums with soft substrate, excellent filtration, secure covers and carefully chosen tankmates. Although juveniles are often sold at a manageable size, this is a specialist predatory fish that grows very large and needs long-term planning.

Common Name:
Golden Fire Eel, Fire Eel, Fire Spiny Eel, Golden Fire Spiny Eel

Scientific Name (Latin):
Mastacembelus erythrotaenia

Strain / Form:
Golden / high-colour trade form

Maximum Size:
Approximately 80–100 cm

Water Type:
Freshwater

Origin / Natural Habitat:
The Golden Fire Eel is a colour form of the Fire Eel, a freshwater spiny eel from Southeast Asia.

In the wild, Mastacembelus erythrotaenia is associated with rivers, floodplains, slow-moving waters, marginal vegetation, submerged roots, muddy areas and soft-bottomed habitats.

It spends much of its time hidden among cover or partly buried in soft substrate, emerging to feed and explore, especially during quieter periods.

Water Parameters:
Temperature: 24–28°C
pH Range: 6.5–7.5
Hardness: Soft to moderately hard
Ammonia/Nitrite: 0 ppm
Nitrate: Kept low and stable
Oxygenation: Good oxygenation and strong filtration required

Temperament:
Predatory / Semi-Aggressive

Golden Fire Eels are generally peaceful towards fish too large to swallow, but they are predatory and will eat small fish, shrimp and other suitably sized tankmates.

They are best kept with calm, robust fish of suitable size. Avoid aggressive species that may bite, bully or compete too strongly with the eel around hiding places.

Diet:
Carnivore / Bottom Predator

The Golden Fire Eel should be offered a varied meaty diet.

Suitable foods include bloodworm, earthworms, river shrimp, prawns, mussel, cockle, krill, chopped fish, blackworm and quality carnivore sinking foods where accepted.

Young specimens often prefer frozen or live-style foods, while settled adults may learn to take prepared sinking foods.

Avoid feeder fish, as they can introduce disease, encourage poor feeding habits and are not a balanced long-term diet.

Minimum Tank Size:
Approximately 500–700 litres for long-term care

A very large aquarium footprint is essential, with length and floor space being especially important.

Juveniles grow over time and should not be purchased for small aquariums unless a suitable large upgrade is already planned.

Behaviour & Activity:
The Golden Fire Eel is usually secretive during the day and more active at dusk, after dark or when food is offered.

It may bury itself in soft sand, rest under wood, use caves or hide among smooth rockwork and plants.

Settled individuals can become confident and may learn feeding routines, but they still need secure hiding areas to reduce stress.

Community Suitability:
Large Predator Community / Tank Buster

The Golden Fire Eel is suitable only for large specialist aquariums with carefully selected tankmates.

Suitable companions may include larger peaceful catfish, large barbs, larger rainbowfish, robust peaceful cichlids with caution, sizeable plecos and other fish too large to be swallowed.

Avoid small tetras, rasboras, guppies, shrimp, small corydoras, delicate fish, fin-nippers, aggressive cichlids and any fish likely to harass the eel or fit in its mouth.

Special Requirements or Care Notes:
This is a large specialist fish and should be planned for at adult size.

Provide soft sand or fine smooth substrate, as rough gravel can damage the underside and delicate skin.

Offer plenty of hiding places using smooth caves, large driftwood, pipes or stable rockwork.

Avoid sharp décor and unstable structures that may collapse if the eel burrows underneath.

Maintain excellent water quality with strong filtration and regular water changes, as large predatory fish produce heavy waste.

Keep the aquarium tightly covered, as spiny eels can escape through surprisingly small gaps.

Fire Eels can be sensitive to some medications, especially copper-based treatments, so always check treatment suitability before use.

This species is best suited to aquarists with experience keeping large oddball or predatory freshwater fish.

Suitable for:
Experienced

Availability:
Availability can vary depending on season, supplier, size and colour form.

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.