Mastacembelus erythrotaenia – Fire Eel

Mastacembelus erythrotaenia or Fire Eel is one of the larger Spiny Eels, growing to a maximum total length of around 100 centimeters. This species lives in Laos, Vietnam, Cambodia, Thailand, Malaysia and Indonesia.


Mastacembelus erythrotaenia – Fire Eel

Mastacembelus erythrotaenia was officially described by Bleeker in 1850. The genus name can be broken down into two ancient Greek words. Mastax means “to bite” and emballo means “to throw oneself.” Together it means something like, throwing oneself up somewhere biting. The species name erythrotaenia also comes from ancient Greek and means “with red stripes”. Their common name is Fire Eel.

They are part of the family Mastacembelidae or the Spiny Eels. The family has 3 genera and about 86 species. They owe the name Spiny Eelsto the clearly separated spines on their back. These spines are harmless to humans. The eels can be distinguished from other eels by their long nose and tubular nostrils.


Fire Eels can reach a total length of about 100 centimetres. It is therefore one of the largest spiny eels. They have a dark brown ground colour. A few bright red stripes run backwards from the head. At about 1 / 5th of the body, these stripes turn into round red dots with a darker brown border around them. Some specimens have a red band on the pectoral, dorsal and caudal fin, others lack this red band. The belly side is a bit lighter in colour.

The Fire Eel is a fairly calm fish. They usually leave other species alone. You can tame them so that they come to get food out of tweezers. For this, you can use a whistle as a sign that there is something to eat. Some hold the food with their fingers. Keep in mind that they sometimes miss the food and can bite your finger.

By the way, they are nocturnal animals. They are most active at dusk and during the night.

Maximum age

When purchasing these fish, keep in mind that they can get fairly old. With proper care, they can reach an age of 15 to 18 years! With the right aquarium design, care and fellow residents you will enjoy your Fire Eel for a long time!

Sexual Dimorphism

The difference between the male and female is difficult to see in Mastacembelus erythrotaenia. The males and females are of the same colour and the same length. Adult females seem to be slightly bulkier when ready to spawn.

Mastacembelus erythrotaenia - Fire Eel
Mastacembelus erythrotaenia – Fire Eel


The habitat of the Fire Eel is in South East Asia. You can find them in Cambodia, Indonesia, Laos, Malaysia, Thailand and Vietnam. They inhabit the slow-flowing waters where a muddy bottom can be found. They use the mud to hide in during the day. Mostly buried in the mud, often only their noses can be found above the mud.


In the wild, Mastacembelus erythrotaenia is omnivorous. They feed on small invertebrates, small fish but also small amounts of vegetable matter. However, they clearly prefer meaty foods.

In the aquarium you can feed them krill, shrimp, smelt, etc. Frozen food such as Daphnia, mosquito larvae and the like are eaten, but ultimately do not contain enough nutrition for an adult Fire Eel.

The Aquarium

Despite this growing up to be a tall fish, a relatively modest aquarium is required. An aquarium from 200 centimetres is sufficient. For young specimen, you can use a smaller aquarium. Ultimately it will be fish of a meter length!

The Fire Eel is relatively peaceful towards other fish species. The only condition is that they are big enough not to be eaten. Keep them together with somewhat larger, calm fish species.

Mastacembelus erythrotaenia can sometimes react aggressively towards conspecifics. You should therefore preferably keep them alone or in a group of more than five copies.

Decorate the aquarium with sand on the bottom that is not sharp, for example, filter sand. They like to bury themselves in the substrate during the day or in bright light. Provide sufficient hiding places where they can hide. A few PVC pipes where they can hide their long body works great.

As mentioned, they are mainly active in the twilight and night. So take lighting into account. Make sure it is not too bright. If you buy lighting with a dimmer and light computer, you can also adjust the times slightly. Make sure you create a twilight when you want to see or feed the fish.


They are true escape artists. They can crawl through any small hole and exit the tank. Make sure that all openings in the aquarium are properly closed. A small opening is enough for a Fire Eel to escape from your aquarium!

Water parameters

This species is not very sensitive to water values. They thrive at a temperature of around 24 to 28 degrees Celsius. They can handle a pH of 6.0 to 8.0 and a water hardness of 5 to 12 GH. As with all other fish, clean water is appreciated. Regular water changes are also necessary due to the diet.

Breeding Mastacembelus erythrotaenia

Not much is known about breeding Mastacembelus erythrotaenia. Occasionally fry are born in the aquarium. These are always random breeds. There are no instructions on how to induce them to breed.



John de Lange

Copyright foto’s

Nonn Panitvong –


Additional information





Breeding behaviour




Length minimum in cm

Length maximum in cm

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