Slithering and glittering fire eel in water make a bizarre panorama effect in the aquarium.

To understand a fire eel, you need not confuse this creature with the eels, as these are pure fishes with an elongated body structure and movements of a snake.

Despite their enormous size and dragon-like features, these fishes are harmless to humans and totally safe for home aquariums.

Many fish lovers are attracted to these fire eels’ stunning persona and quick crawling movements, and they selectively get them for their living room’s fish tanks.

This is a complete care guide providing all the necessary information about the fire eel, including the instructive manual on how to keep them safe & healthy in fish tanks.

Brief Specifics

Species Details
Scientific Name Mastacembelus Erythrotaenia
Other Common Names Fire Eel, Golden Fire Eel, Firetrack Eel, Blue Fire Eel, Red Eel
Family Mastacembelidae
Origin Southeast Asia: Indonesia, Malaysia, Myanmar, etc
Approximate Age Ten years
Length 100 cm
Fish Type Freshwater
Shade Brown or Grey
Approx. Price $25

Source & Habitat

This fish belongs to the same family of spiny eels that originated in Africa and Asia, dwelling in fresh and brackish water, and was first identified in 1850.

In contrast, the fire eels are slightly different, typically in size and habitats. It is densely found in the freshwaters of Southeast Asian countries, especially in Myanmar, Vietnam, Cambodia, and some parts of Indonesia, Thailand, and Malaysia.

Due to unaccounted aquatic trade in many areas, these are almost extinct from Thailand, which is considered among its source regions.

They prefer to stay close to the water bed or mostly entombed in the mud. This is why it usually dwells in waters with slow movements, typically in muddy regions, ponds, or rivers.

How Big Does a Fire Eel Get?

With their protracted body structure, these are large size fishes. A full-grown fire eel attains a total length of about 40 inches.

It is a wild fish that usually grows to its maximum length if it stays in open waters where it can travel extensively and predate its food.

If you maintain them in aquariums, the size of a fire eel may only reach half of its potential, ranging from 18 to 21 inches.

What Do They Look Like?

The body shape of the fire eel is long cylindrical with small fins attached to it. The head of the fish is in conical form, with a pointed snout covering its mouth.

The eyes are bold and circular, edging out of the head. At the same time, the nostrils are at the front, next to the antenna-like extension on the snout.

As already explained above, the fire eels belong to the spiny eel family; its most prominent marks are seen in the form of the mini spine-like structures on the upper part of the body ending to the dorsal fin.

The body flattens towards the end before the beginning of the caudal fin and becomes the fish’s tail.

Fire Eel - Guide for Care & Breeding

Color

The fire eel’s color is a dark shade of brown or grey on the top, while the darkness reduces at the bottom. Some peculiar color patterns are also visible all over the fish.

The fish contains bright red dots or lines all over the body, whereas the front portion of the body, including the head, has red-colored broad strips.

The soft side of the pectoral fins portrays white margins with dark outlines perpendicular to the fin. Other fins (caudal, anal, dorsal) are darkly shaded.

Average Life Expectancy

This is a typical wild habitat fish that survives the tropical climate conditions very well. The total lifespan of fire eel is up to 20 years, dwelling in the freshwaters comfortably feeding itself.

But if they are raised in a homely background by artificially creating ideal environmental conditions, their average lifespan decreases to almost half of its actual age.

In aquariums, they only stay around ten years, which usually happens due to decreased metabolic activities in a closed space.

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Sex: Male vs. Female

Gendering the fire eel is exceptionally difficult since recognizing the comparative difference of the two body structures rather than exact signs is the only way out.

Here are a few notable gendering differences of the fish:

  • The males have a glistening body, while females are dimly shaded.
  • Females are more prominent than males.
  • The male brightens its colors during the breeding season.
  • The females look fat during the breeding season.

Cost and Availability 

With high popularity in Asian & African countries, a large portion of the fire eel market is dedicated to fish consumers in their diet. At the same time, they are equally purchased for aquariums too.

The fish is priced high due to continuous demand in multiple trades with its extensive reach internationally.

In the international market, the fire eel for sale is available at around $20 to $30 and varies depending upon the import & export duties charged.

The Complete Care Guide

Quick Look at Care Sheet
Care Level Easy to Moderate
Social Territorial
Predators Yes, Piscivores (Can eat anything of small size)
Temperament Semi-Aggressive
Diet Carnivore
Breeding  Difficult in Captivity

What Do Fire Eels Eat?

Originally the fire eels followed the carnivore diet in the rivers and natural water bodies. These are reported to be stringent predators and look out for their food (insects, worms, algae, plants, etc.) during the night.

Fire eel’s diet usually consists of small aquatics such as fishes, crabs, insects, and worms. These fishes hunt for food on a daily basis; hence living creatures are an excellent food choice for them in fish tanks. While on certain occasions, they also consume vegetarian food.

You can provide multiple food items, and instead of dropping the particles in the tank, you can try feeding them directly into their mouth. This method helps record the fish’s daily diet chart and prevents over-eating.

Here is a list of feeds you can offer to the fire eel in the aquarium, selectively live or frozen:

  • Small fishes (living feeders)
  • Bloodworms
  • Tubifex
  • Snails
  • Insect Larva
  • Daphnia
  • Brine Shrimp
  • Mysis Shrimp
  • Prawns
  • Krill
  • Lance fish
  • Green Vegetables
  • Sea urchins

Pro Tip: Fire eel avoids eating flakes or pellets and even plant matter such as algae. So do not bring these items for feeding them.

General Behavior

These are typical nocturnal fishes as they spend most of their daytime under the mud with snout pouting out slightly and coming out of it in the dark hours to find the prey.

Low dim lighting becomes a suitable environment for them as they avoid coming out of their caves, burrows, or hiding spaces in bright light.

As they grow old, fire eel’s behavior towards other fishes becomes accommodating and usually stays in its solitude, roaming around or lying down. Still, it does behave aggressively with other mates to prove its territory.

Breeding in Tanks

It is listed among the most annoying aquatic when it comes to breeding in artificial terrain.

No matter the catalytic methods used, from creating favorable conditions to using hormonal injections, reproducing young ones from this parent in captivity becomes a long hectic process.

Initial Setup for Mating

Fire eel reaches adulthood to reproduce at the age of twenty-five months. So it would be best if you got a healthy, eligible pair of these fishes in a tank.

You should prefer feeding them with protein-rich food.

The tanks should have the capacity to hold 100 gallons of water and keep it at about 30 degrees Celsius. Arrange a proper oxygenation system in the tank for freshness.

Spawning

Once the fishes are ready for mating, the male and female fire eel starts moving together in the tank. You can lower the light intensity and leave them alone for some time.

Females lay the eggs in multiple slots, which are yellowish.

In total, there are about 900 eggs settled down on the surface.

Hatching

You should keep checking if the mating process is finished, as, after that, the fishes may start eating the eggs. So put both the female and male fire eel in another tank.

And improve the purity of the water by filtering about 50% of the tank water.

The eggs will hatch to produce larva in 2 to 3 days and feed over the egg yolk for approximately one week. After crossing this period, you can provide the fry with baby shrimps at least four times a day.

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The baby fire eels will reach three inches in about 60 days.

Note: Turn off the filters and oxygen system after the eggs hatch. Shuffle the water regularly and add antibiotics to keep the water clean.

Diseases Hampering its Healthy Life

Fire eel is particularly delicate with its living conditions and quickly loses its health due to injuries or infection. Experts advise regularly examining the fish’s skin, behavior, and movements to detect any possible troubles and get them cured soon.

Living habitation is one of the leading causes of most illnesses in the fire eel. Hence, experts repeatedly advise it to apply a robust water filtration system and use antibiotic solutions to treat any infections in the water.

It would be best to clean the substrate regularly to remove leftover food and excretion. Another possibility is rough substrate particles that may injure the fish when trying to bury itself. So essentially, choose a soft substrate for the tank.

Symptoms of a Healthy Eel

You can scrutinize the fish on the following parameters for a healthy fish.

  • The eyes should be clear, open, and shiny.
  • The fish should spend most of its time in and around the substrate.
  • It should eat comfortably.
  • The color shades of the fish should stay in its shining statue.
  • The skin should look clean.

Common Diseases

  • Bacterial Infection: It happens due to poor water quality and causes cloudy eyes with reddening boils on the skin. You can cure this by cleaning the tank and applying antibacterial tonics under the veterinarian’s guidance.
  • Ich: This might have occurred due to injuries and thus forming white spots on the body. It gets noticeable as it behaves uncommonly with rational movements in the tank. Seclude the fish and apply proper medications.
  • Open Abdomen: This is observed when the fish starts avoiding food. You can choose to provide alternative supplemental food.
  • Cottonmouth or Columnaris: This happens due to parasitic infections when cotton-like white growths appear on the body and around the gills. You should isolate the fish and add medicines to the tank after cleaning the tank.
  • Light-colored lesions on the body: This is another symptomatic disease caused due to Epistylis parasite and has a standard treatment of purifying the tank water.

Tank Arrangements

Quick Stats
Tank Size 350 Litres
Water Temperature 75 to 82 F
Hardness Range 5 to 19 dGH
Tank Lighting Low light
Water pH Level 6 to 8
Tank Type Community tank with large fishes
Substrate Soft sand & rocks, driftwood
Brackish No

Tank Capacity

The ideal size of this fish in open water is one meter which is challenging to hold in a fish tank. But fortunately, if a fire eel baby is petted in a tank, it will not grow more than 1.5ft in length.

Hence to get a fish of such humongous size (18 inches) in an aquarium, you need to install a tank size of more than 80 gallons to accommodate one fish and a minimum of 100 gallons if you are introducing more tankmates.

Tank Internal Setup

Fire eels are clumsy and picky in terms of their living area and use almost everything on their way to either hide themselves or scratch the body. So it is best recommended to put in some useful contents in the tank instead of filling it with just water.

Plants

Plants are the best choice to create a natural look inside the tank, and it soothes the eel and helps keep it calm. Here you can put in a few floating plants, as the fire eels are habitual diggers and would pull out the plants from the substrate.

There is a long list of plants to float over driftwood in the tank. Anubias are highly preferred in fish tanks. Water lettuce, hornwort, and pennywort are the other few good choices on the list. You can also get java ferns in the tank.

Quick Tip: Choose those plants for the aquarium that can survive in a low light environment because high intensity light is not advised in these fish tanks.

Lighting

Fire eel is a natural nocturnal fish that do not prefer to come out in the daytime. Therefore, putting an extra aquarium light system in the tank will not benefit the fish.

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Instead, you can arrange a dim moonlight system in the tank, which creates a night environment artificially.

You can auto-schedule these lights to turn off after a few hours to provoke the fish to come out and feed.

Substrate

These fishes are prone to dig deep into the water bed to find a hiding space. In this act, it gets skin rashes which swell to form diseases.       

The soft sand or specifically non-abrasive substrate is best suitable for fire eel. Thus you can set about 2 to 3 inches thick layer of the soft substrate in the tank. This will not hurt the fish skin, and it can create multiple such holes.

Aeration & Filtration

Water cleaning is definitely required in this case since these are freshwater fishes. Sudden instants of water impurity in the tank increase the fish’s possibility of skin diseases and other illness issues.

Recycling the water with the help of filters enhances oxygen levels and keeps the water fresh. Thus, keep changing the water as advised by your veterinarian and use powerful filters to keep the tank clean.

Decoration

With a thick substrate and floating plants in the tank, you should also put some decorative elements in the fish tank.

Because they mostly stay hidden in covers, you can put some rock stones with soft edges or driftwood.

A box-like structure or anything that becomes a cave for the fish is also welcomed.

Water Specifics

Fire eels are socially adaptable in nature and get comfortable in normal water conditions.

But, multiple water parameters must be monitored for successful petting and breeding of the fish:

  • Use good quality filtration system, which would eventually keep the oxygenation level high.
  • Maintain the water temperature at around 25 degrees Celsius.
  • The acidity of water should be close to 7 pH.
  • Suitable water hardness is between 10 – 15 dGH.

Friendly Mates in Tank

These fishes have predatorial tendencies and are often behave aggressively to keep a hold in their zones. Keeping more than one of this genre in a tank is never a good choice as they would injure each other to claim the territory.

But this does not mean that they do not go in with other aquatics. You can create a community tank of compatible large fishes, and fire eel won’t mind them. Of course, if kept together with small fishes, they will soon be eaten up.

Some of the compatible fire eel tank mates are listed below:

Frequently Asked Questions

Is a fire eel dangerous to humans?

No, this fish is not dangerous to humans in any way. They are shy and only intake breeds that are smaller than their physical size.

However, their body structure is tricky to handle manually because the small spines on their body can create physical damage.

Are fire eels poisonous?

The fish itself is not poisonous, and even the spines over its body can only scratch the upper skin. It does release some thick toxic liquid when it’s nervous, so you should avoid holding it with bare hands.

This liquid is not fatal but may cause blisters or itching.

What is the growth rate of this fish?

It is a slow-growing fish and takes more than two months to grow up to four inches in length. Later in their life, it takes almost a year to lengthen another four inches.

It attains its entire height in captivity at 4 – 5 years.

Is brackish suitable for fire eel?

These are freshwater pet eels and should only be kept in pure water to maintain ideal health conditions. However, there is a possibility of mixing minimum salt into the water for a limited period, as it is observed that it is beneficial for skin treatment and curing bacterial infection.

Does a fire eel try escaping the tank?

Yes, there is a huge possibility of this fish jumping out of the tank if it ever gets a chance. So, it is always advised to keep the tank closed and keep the lids tight fit.

Does a fire eel prefer eating other fish?

Fire eels are typical carnivores, and hence their eating habits include every fish that fits in their mouth. They generally do not clash with same-sized fishes, but if the fire eel is hungry and a small fish move by, there are rare chances of it getting away alive.

Takeaway

These are undoubtedly one of the spellbinding water animals that you can put in your home tank. Unlike other fishes in the tank, it has a long body with waving movements like a snake, which looks terrific.

One of the most promising experiences that you can capture with the fire eel is to feed them directly from your hands, and not to mention, these are harmless to humans.

These can be purchased and captivated anywhere globally, provided the owner maintains a compatible atmosphere and follows fish-specific guidelines to keep them fit & alive for long years.

About the Author

Shelby Crosby

Shelby is a passionate fishkeeper who has been writing about fish for over 5 years. She is a pro aquarist and holds a BSc Honors Degree in Wildlife and Fisheries. She creates her own beautiful aquarium layouts and loves to share her knowledge of tropical fish with other hobbyists.

Career Highlights:

  • Has worked with several aquarium manufacturers as a consultant
  • Organized and hosted workshops on freshwater fish keeping at retail stores, educational facilities, and libraries
  • Released content for the amphibian community through her writings

Educational Highlights:

  • BSc Honors in Wildlife and Fisheries in 2011 (University of Northern British Columbia)
  • Completed her undergraduate thesis on the effects of zoochlorella supplementation on the growth and health of fish.

Writing Experience

Miss Crosby is a Freelance blogger; many of her articles are posted online on various blogs. She has also written a few short articles for "Tropical Fish Hobbyist Magazine" in the past. She is a regular contributor to FishParenting.com. Her education, first-hand experience with fishkeeping, and in-depth knowledge in aquaculture make her one of the most competent writers in the industry.

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