If you are considering an oddball addition to your fish collection and have some experience in fish parenting, it’s time to consider Tire Track Eel.

It looks like an eel. The reticulated pattern on its body resembles tire marks, explaining its name.

They have intrigued researchers and hobbyists alike by their close resemblance with the Zig-Zag Eels. You will still come across many articles treating them as one.

Both are sold interchangeably in the fish trade to date.

This article provides complete information and guidance on caring for it.

Generic Facts

Table 1 – Generic facts
Scientific Name MastacembelusFavus
Other popular names** Tire Track Eel, Tiretrack Eel,Spiny Eel*,Zig-Zag Eel**, White Spotted Eel**, Marbled Spiny Eel**
Family Mastacembelidae
Origin Southeast Asia
Life Span 8 to 18 years
Adult Size 20 to 24 inches
Type Freshwater
*It is a generic name for the species (Mastacembelidae) consisting of wide varieties. **These are different species from the same family and should not be confused.

Habitat and Origin

Originally from Southeast Asia (India, Thailand, and Myanmar), it is prominently found in western Malaysia and Thailand.

There are about 73 different species of Spiny eels found in freshwaters from Africa to China.

Among these, Tire-track Eels are popularly captivated since they are relatively smaller.

They thrive in still to slow-moving waters.

During the day, they bury themselves in the sandy bottoms or hide in rocks.

At night they actively hunt for food and scavenge the river beds.

Did you know? Tire Track Eels are a delicacy in Asia and are traded as seafood globally.

Physical Attributes and Size

Let us begin by understanding the anatomy of Spiny Eels to differentiate the Tire-track Eel.

Anatomy of Spiny Eel

Image credit: britannica

All spiny-eel fish have the same broad structure.

Their bodies are worm-shaped and slippery like eels. The anal and dorsal fins merge into their tails, forming a deep u-shape around their latter bodies.

They have many spines preceding their dorsal fin (on the upper bodies) and a few spines before their anal fin (in the lower bodies). This explains their name.

They have long mouths, with upper portions snouting like an elephant trunk.

Let us understand what differentiates them.

Differences in colors, markings, and the average number of spines on their bodies define their unique species.

A study (on “Systematic Review of the Mastacembelidae or Spiny Eels of Burma and Thailand, with Description of Two New Species of Macrognathus”) indicated the following types:

Image credit: jstage.jst.go.jp

Fig. 2. Mastacembelus of Burma and Thailand. a, M. alboguttatus, 183 mm, Salween River at Mae
Sariang; b, M. armatus, 142 mm, Mekong River at Bung Karn; c, M. armatus, 342 mm, Tapi basin,
Khlong Sok; d, M.favus, 165 mm, Ubon Ratchatani: e, M. ,favus, 386 mm, Tapi basin, Khlong Sok.

Tyson R. Roberts observed the following differences between the two species:

MastacembelusArmatus (Fig 2b and c) – Zig-Zag Eel MastacembelusFlavus (Fig 2d and e) – Tire Track Eel
Number of dorsal spines (34-40) or an average of 37.3 Number of dorsal spines (33-37) or an average of 35.2)
Coloration – Highly variable, with a few species having no color at all Coloration – is bright
Pattern – Long lines cover their bodies in a zig-zag pattern. The pattern consists of continuous or multiple broken lines. A network pattern forms when several lines meet and intersect   It covers two-thirds of the body till the dorsal fin (or abdomen) and fades out or disappears latter portion Pattern – is reticulated, better developed, continuous, and pronounced   It covers the entire body post the abdomen uniformly
Body – Slender Body – Deeper, rounder, and fuller
Distribution: India, Myanmar, Thailand Distribution: Western Malaysia, Thailand

In captivity, the Tire Track Eel can grow up to 20 inches in size. However, it may grow 24 to 26 inches long with proper care.

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It is 4 to 6 inches when sold. You will need a larger tank as they mature.

The growth rate is gradual, but more specific information is unavailable since it is often confused with other fish-eel(s) in the hobbyist circle and fish trade.

Likewise, the lifespan varies drastically in captivity based on care and other genetic factors.

Their bodies are light brown with a striking contrast-colored pattern, giving them a vibrant persona.

Natural Self-defense

Male Vs. Female

The male and female Tire Track Eels cannot be distinguished unless they breed. However, a mature female looks more rounded than her male counterpart.

Typical Behavior Patterns

  • As shy, nocturnal bottom dwellers, they burrow in the sandy bottoms or hide in caves, rocks, etc., during the day.
  • Actively hunt and scavenge for food at night.
  • In the wild, they eat anything smaller they come across, including submerged plantations.
  • Find out about Bichir nocturnal (super active at nighttime) fish species.
  • They keep to themselves and gel well with non-interfering, peaceful tank mates.
  • However, they will not think twice before feasting on slow-moving, smaller tank mates.
  • Get aggressive with predatory tank mates.
  • Tend to get aggressive amongst themselves to define and defend their territories.
  • Love solitude. They do not move in groups.
  • Hence, it is advisable to add only a single Tire Track Eel to your tank unless your tank is large enough for them to demarcate their individual territories.
  • They have tiny scales, making them sensitive to changes in water quality and prone to diseases.
  • May refuse to eat for a few days in a new environment.
  • Requires time to adjust.
  • Survive without food for a week.

How to Buy

The Tire Track Eels are saleable when they are 4 to 6 inches long.

Sellers often sell them interchangeably under the same name.

Since you know how to differentiate it from its cousin Zigzag Eel, make sure you buy the correct one.

Always buy from a reliable source, be it online or offline. Follow the instructions carefully to avail of the after-sale support.

The chances of it having unidentified issues while growing/surviving in captivity are higher when you buy a newly arrived stock or a newborn fry.

Hence, always buy from older stock in the shop.

Check with the seller how long the fish-eel has been with them in their tank and ask about their tank water parameters.

Upon receipt of the pet fish-eel by courier or before selecting one personally, inspect them physically for any spots, color issues, wounds, etc.

Improper transportation and handling can also cause stress or damage to the fish.

Initiate the acclimating process only after you are satisfied with the above points.

Care Guide

Table 2 – Care Overview
Care Level Intermediate
Diet Omnivore
Temperament Shy, Peaceful with tank mates but are aggressive within own group (species)
Breeding Difficult in captivity / Egg laying
Social Loner, Nocturnal Predator, and Scavenger

Food

Tire Track Eels eat almost anything smaller than them in the wild.

They actively scavenge the bottom waters for worms, crustaceans, insect larvae, small fishes, fish eggs, etc. Some also eat submerged plants.

However, it is difficult to feed them in captivity.

Their diet is so varied that you need a trial and error method to identify the foods they love to eat.

Initially, they might refuse to eat for the first few days.

They can survive up to a week without food. Take it easy and focus on comforting them.

How and What to Feed

Considering they are bottom-dwellers use sinking foods to reach them.

Feed in small portions several times and wait for them to eat.

Notice the food they readily eat. Feed a variety of food to maintain good nutritional value.

Everything you feed should be high quality to avoid parasitic/bacterial infection.

They scout the tank bottoms every night. Hence, feed them only once or twice a week.

They may refuse to eat when not hungry, but generally, they eat all the time. Avoid overfeeding.

See also  Opaline Gourami Care: Tank Setup, Tank Mates, and Feeding Details

Observe to ensure they are growing well and not over/malnourished.

Additionally, filter the uneaten food and bottom waste regularly, as it will impact their health if the tank water quality drops.

In the beginning, try leaving little food morsels at the cave entrances and in their hiding spaces in the tank decor at night.

They are likely to eat it in the dark. Ensure other tank mates do not eat their share of food.

You can feed

  • Live foods – Earthworms, black worms, blood worms, small fishes, krill, prawns, brine shrimps, etc.
  • Plankton and other vegetation (some may accept it).
  • Prepared food tablets (some may refuse these).
  • Pellets, Flakes (moisten, so it sinks).
  • Frozen foods – defrost before feeding.
  • Meaty foods.

Breeding

Tire Track Eels have not spawned in captivity to date.

They mate before the flooding season in the wild. The eggs and sperm they release fertilize in the water.

No authentic information about their mating behavior, breeding, fertilization, and growth from fry to adult eel is available.

Few articles have confused the information on Zig-Zag Eels as relating to them.

Simulating a pre-flood-like environment in the tank water and feeding them with high protein food might induce them to breed. But no such precedent has been reported so far.

Challenges in Captive Breeding

  • They are territorial within their group and grow up to 26 inches long.
  • The tank size for adding even one fish-eel is a minimum of 75 to 125 gallons.
  • Hence, most cannot add more than one fish-eel to their community tanks, ruling out any scope to breed.
  • Even if you add more than one, you cannot know their gender till they spawn.
  • Thus, you will never know if you have a male-female pair to breed.
  • Creating natural pre-flood scenarios in the tank seems impossible as there could be many other parameters in the river water and currents, which are hitherto not identified to replicate breeding season.
  • The pre-flood season months can vary according to the place of origin.
  • This information might not be accurately available in the fish trade (locally or globally, owing to the supply chain involved).

Glimpses from a Study

A study by Gupta, Sandipan & Banerjee, Samir. (2016), in “Food, Feeding Habit and Reproductive Biology of Tire-track Spiny Eel (Mastacembelusarmatus): A Review”, observed the following:

  • Very little research is available about their reproduction.
  • During the breeding season, males become active and brighter in color, while females become heavier and dull in color.
  • A study on the growth of their reproductive organs identified 5 different stages.
  • In the 3rd stage of pre-spawning, yellowish ovaries become large, and the female abdomen swells. Eggs are visible through their stretched skins.
    The male reproductive organ (testes) looks swollen and pinkish due to improved blood supply.
  • In the spawning phase (4th stage), ovaries swell further and eggs ooze out due to abdominal pressure.
    Similarly, the male testes become more reddish due to higher blood circulation and release
    sperm under pressure.
  • In the post-spawning (5th stage), female ovaries shrink in size after releasing eggs, and blood supply to the ovaries normalizes.
    Male testes become semi-transparent and small due to normalized blood supply.
  • There are variations in the reproductive seasons(ranging from March to November)  and spawning months (single or multiple) cited by various researchers at different geographic locations.

Although both (Tire Track and Zig-Zag Eels) are different species and have different scientific names, the research considers them as one.

Secondly, the research on breeding seasons covers only India and Bangladesh.

Probiotic Technology in Breeding – A Success Story

According to a report, a farmer in An Giang province of Vietnam has successfully bred the Tire Track Eels and used probiotic technology to incubate them.

While explaining his production facility, NguyễnBá Sang (the farmer) shared that:

  • They select matured Tire Track Eels from two different sources (rivers and ponds) in a pre-determined ratio. This curbs inbreeding (mating with close relatives) to improve fertility rates and the quality of newborns.
  • High-quality industrial feed having 40-42% protein level is used to nourish females.
  • They start breeding after 3 to 4 months of spawning.
  • Saprolegniasis (a water fungus that eats eggs) is dangerous for the eggs.
  • Hence they use probiotic technology to incubate the eggs and achieve higher fertility rates.
  • Water is filtered, sterilized, and aerated within 12 hours to kill microorganisms.
  • Under a water temperature of 29 degrees C, a salinity of 50/100, and a hatching density of 10 gm/20 liters of water, the Bacillus subtilis incubates within 3 to 4 hours.
  • They move the Bacillus subtilis to an incubation tank after it grows.
  • 85% of eggs fertilize, and 70 to 75% of them hatch. This hatching rate is 10-20% higher than usual (without probiotic incubation).
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He claims that this method is environmentally friendly (reduces water waste), efficient (higher hatching rate), produces healthy frys, and is cost-effective due to higher productivity.

The report does not specify how they identify the gender of the matured track eels for reproduction.

We believe it could be by physical examination of their reproductive organs. As discussed in the earlier section (Glimpses from a Study), few changes are visible in their reproductive organs during the pre-spawning and spawning seasons.

Diseases

Tire Track Eels have tiny scales covering their bodies, making them sensitive to sudden water changes and parasitic/fungal infections.

Considering they are sensitive, utilize only half the dose of prescribed over-the-counter medication for other fishes, if needed.

Their most common disease is Ick (or Ich/White-spot disease).

We strongly recommend you consult a vet for a proper diagnosis and treatment for any disease. Early detection and cure are critical.

Refer for details on the diseases found in freshwater fishes and their prevention.

Acclimating

Tire track Eels rarely breed in captivity.

As a result, any addition you make might be from the wild and captivated by the seller or his sources.

It is vital to de-worm, quarantine, and acclimate your newly acquired pet-eel before adding it to the main tank.

It will ensure the safety of both – the new addition, as well as the existing tank-dwellers.

After acclimating, add your fish-eel to the main tank.

Read here for ways to acclimate a new addition to your home aquarium.

Tank Recommendations

Table 4 – Tank Requirements Overview (Tire Track Eel)
Minimum Tank Size 75 to 125 Gallons (284 to 473 Liters)
Water Temperature 72 to 82 degrees F (22.2 to 27.8 degrees C)
PH Level 6.8 to 7.2
Water Hardness 5 to 15 dGH

Tank Size

Juvenile pet eel up to 6 inches can live in a 35 to 40 gallons tank. However, considering they grow up to 26 inches long, you will need a bigger tank as they mature.

As discussed earlier, add only one pet eel in the tank, as they are loners.

If you wish to add more, make sure the tank is large enough for each of them to have their own differentiated territories to avoid aggression and stress in the tank.

The tank should be longer.  Height can be smaller. 

Tank Setup

The purpose of tank setup is to replicate a tank environment closest to its natural habitat. It makes your pet fish feel safe, healthy, and happy.

Substrate

Since they remain hidden in the natural environment, use fine sand and gravel substrate for them to burrow safely.

Lighting

Use a soft medium to dim light.

Plants

Use floating plants as

  • It will pull out other plants from the tank bottom while hiding/scavenging, spoiling your decor.
  • They will soften the tank lighting, replicating its natural surroundings.

Driftwood, Java Moss, Java Fern, etc are suitable. Even artificial floating plants can be used. 

Read in detail about Floating Plants for your Home aquarium.

Decor

Create abundant hiding spaces like caves, rocks, tunnels, etc.

Be creative with colors and materials to beautify your tank.

Ensure everything has rounded edges. The material of decor should be safe and free of bacteria/parasites.

The tunnels, caves, and all open holes should be spacious enough to swim through.

Leave space between the decor for it to hide safely without hurting itself (to prevent wounds, scratches, etc.)

Consider using PVC Pipes, Ceramic or clay tunnels/caves, Rocky caves, rocks, etc.

Explore how Star Wars themed fish tank-decorations can be ideal for a large aquarium.

Oxygen and Filtration

All aquariums need oxygen and filtration to oxygenate the water, create water currents, and keep the tank water clean.

Visit for more on natural, biological, and chemical filtrations.

Tank Mates

Ideal tank mates for this fish-eel should not be

  • Small enough to be their meal.
  • Territorial, Aggressive, or interfering with them in anyways.
  • Predators who can feast on small, medium, or large-sized fish-eel.

Knifeshifh, Gouramis, Acara, and Geophagus make good tank mates.

Frequently Asked Questions (FAQs)

Everything you want to know about them has been covered so far, except the following queries.

Should I add salt to the tank water before adding a Tire Track Eel?

They are freshwater fish-eels. They don’t need salt water. However, you may add 3 teaspoons of aquarium salt/per 2.5 gallons of water.

Can Tire Track Eel survive in brackish water?

Brackish water is slightly saline water, which is less saline than the sea (marine) water. It occurs naturally in places where rivers meet the sea.

This fish-eel is tolerant to salinity up to 1.000 to 1.005, which is the same as 2 teaspoons of aquarium salt/per 2.5 gallons of water.

However, a freshwater aquarium is preferable, considering the requirements of other tank mates.

Conclusion

Tire Track Eels are certainly not recommended for beginners.

If you have prior experience, this quirky fish-eel will make an unorthodox addition to your collection.

Also know about the Quirkiest Fish Upside Down Catfish.

Definitely, your tank will not have any dull moments at night, thanks to their presence.

We wish you a happy fish-parenting time!

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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