Peacock Eel Care Guide

peacock eel


The Peacock Eel, scientifically known as Macrognathus siamensis, is a fascinating fish species originating from Southeast Asia, including countries like Thailand and Indonesia. This elongated fish exhibits unique characteristics and features that make it a captivating addition to aquariums.

Unique Features and Characteristics

One of the standout features of the Peacock Eel is its elongated, snake-like body, which can reach lengths of up to 12-16 inches (30-40 cm). Its body is adorned with beautiful iridescent colors, resembling the vibrant plumage of a peacock’s tail, hence its common name.

Peacock Eels are known for their exceptional burrowing abilities. They possess a slender, elongated shape that allows them to navigate through substrate and create burrows or hide among decorations in the aquarium. This behavior adds an interesting dynamic to the tank environment.

Despite their striking appearance, Peacock Eels are generally peaceful fish. However, they can exhibit territorial behavior towards their own kind, so it’s important to provide sufficient hiding places and space for each individual. Additionally, they are primarily nocturnal, often displaying increased activity during nighttime.

Summary Table

Common NamePeacock Eel
Scientific NameMacrognathus siamensis
Origin/DistributionSoutheast Asia, including Thailand and Indonesia
SizeUp to 12-16 inches (30-40 cm) in length
Aquarium SizeMinimum 40 gallons (150 liters)
Water ParametersTemperature: 75-82°F (24-28°C), pH: 6.5-7.5, Hardness: 5-15 dGH
DietCarnivore; prefers live or frozen foods such as bloodworms, brine shrimp, and small crustaceans
Feeding FrequencyOnce a day
TemperamentGenerally peaceful, but can be territorial with its own kind
TankmatesCompatible with non-aggressive community fish; avoid keeping with small fish that can be seen as prey
BreedingBreeding in captivity is challenging and rare; requires specialized conditions
LifespanAround 8-10 years in captivity
Care LevelIntermediate
Unique Features/AppearanceElongated, snake-like body with beautiful iridescent colors resembling a peacock’s tail
Conservation StatusNot evaluated (NE)
Additional NotesPeacock Eels are known for their burrowing behavior, so provide plenty of hiding places in the aquarium. They are primarily nocturnal and may be more active at night.


The Peacock Eel belongs to the following taxonomic classification:

  • Common Name: Peacock Eel
  • Scientific Name: Macrognathus siamensis
  • Family: Mastacembelidae
  • Order: Synbranchiformes

The common name, “Peacock Eel,” is derived from the fish’s vibrant coloration, reminiscent of a peacock’s tail, combined with its elongated body shape. The scientific name, Macrognathus siamensis, reflects the genus (Macrognathus) and species (siamensis) to which the fish belongs.

The Peacock Eel is a member of the Mastacembelidae family, which consists of various species commonly known as spiny eels or mastacembelids. This family includes other interesting eel-like fish known for their elongated bodies and unique behaviors.

In terms of order, the Peacock Eel belongs to the Synbranchiformes order, which encompasses a diverse group of fish species characterized by elongated bodies, absence of pelvic fins, and specialized adaptations for burrowing or inhabiting aquatic environments with low oxygen levels.

Natural Habitat & Distribution

The Peacock Eel (Macrognathus siamensis) is native to Southeast Asia, specifically found in countries such as Thailand and Indonesia. Within its geographical range, it can be encountered in various freshwater habitats.

In the wild, Peacock Eels inhabit a range of environments, including rivers, streams, canals, and even rice fields. These fish are well-adapted to living in tropical regions with warm water temperatures and a diverse array of aquatic flora and fauna. They are often found in areas with dense vegetation, submerged roots, and debris, which provide them with hiding spots and shelter.

Due to their burrowing nature, Peacock Eels are known to inhabit sandy or muddy substrates, where they can create tunnels and burrows for shelter and protection. This behavior allows them to establish their territory and seek refuge when necessary.

It’s worth noting that the Peacock Eel’s natural habitat consists of slow-moving or stagnant waters, where oxygen levels may be lower. They have evolved to tolerate such conditions, and their labyrinth organ enables them to breathe atmospheric air, allowing them to survive in areas with limited oxygen availability.

Understanding the natural habitat and distribution of the Peacock Eel helps aquarists create a suitable environment in captivity that mimics their preferred conditions, ensuring their well-being and replicating their natural behaviors as much as possible.

Physical Appearance


Peacock Eels (Macrognathus siamensis) can reach an adult size of approximately 12-16 inches (30-40 cm) in length. Their slender and elongated body shape contributes to their impressive size.

Coloration and Patterns

These eels exhibit a striking and eye-catching coloration. Their body is adorned with a mix of iridescent shades, including hues of blue, green, and gold, resembling the vibrant colors found in a peacock’s tail. The iridescence of their scales can vary depending on the lighting conditions, creating a shimmering effect that adds to their visual appeal.

Body Shape and Fin Structures

Peacock Eels have a streamlined and cylindrical body shape, tapering towards the tail. They lack pelvic fins, which further contributes to their elongated appearance. Their dorsal and anal fins extend along most of their body, merging seamlessly with the caudal (tail) fin. These fins aid in propulsion and maneuverability, allowing them to navigate through the water with ease.

Sexual Dimorphism

Sexual dimorphism in Peacock Eels is challenging to distinguish visually. Male and female individuals have similar external appearances, making it difficult to differentiate them solely based on their physical characteristics. Typically, it requires close examination of their reproductive organs or behavior to determine their sex accurately.

The captivating physical appearance of Peacock Eels, with their shimmering colors, elongated body shape, and unique fin structures, adds to their allure and makes them a visually appealing choice for aquarium enthusiasts.

Behavior & Temperament

General Behavior

Peacock Eels (Macrognathus siamensis) are generally peaceful fish with a calm demeanor. They are known for their docile nature and can coexist peacefully with a variety of tankmates. However, it’s important to note that individual personalities may vary, and some Peacock Eels can display territorial behavior, especially towards their own kind.

Social Interactions with Other Fish

Peacock Eels are solitary by nature and do not exhibit schooling behavior. They prefer to spend their time exploring their environment, burrowing into the substrate, and seeking out hiding places. While they may not actively interact or form social bonds with other fish, they can coexist peacefully in a community aquarium.

Suitable Tankmates

When selecting tankmates for Peacock Eels, it’s important to consider their peaceful nature and specific requirements. They generally get along well with non-aggressive community fish that are not small enough to be seen as prey. Some suitable tankmates include peaceful tetras, gouramis, larger peaceful cichlids, and other species of similar size and temperament.

It’s essential to avoid keeping Peacock Eels with overly aggressive or fin-nipping species, as this can lead to stress, injury, or damage to their delicate fins. Additionally, be mindful of the size difference between the Peacock Eel and its tankmates to prevent accidental predation or aggression due to perceived competition.

Aquarium Requirements

Minimum Tank Size

Peacock Eels (Macrognathus siamensis) require a spacious aquarium to accommodate their active nature and growth. A minimum tank size of 40 gallons (150 liters) is recommended to provide ample swimming space and accommodate their elongated body.

Water Parameters

Maintaining suitable water parameters is crucial for the health and well-being of Peacock Eels. The ideal water temperature for them ranges from 75-82°F (24-28°C). The pH level should be in the slightly acidic to neutral range, around 6.5-7.5. Additionally, the water hardness (GH) should be kept within the range of 5-15 dGH.

Filtration and Aeration Needs

Peacock Eels thrive in well-filtered aquariums with efficient biological and mechanical filtration systems. Good water circulation and oxygenation are important to ensure optimal water quality and to replicate their natural habitat. Consider using a combination of sponge filters, power filters, and/or canister filters to maintain a clean and oxygen-rich environment.

Substrate Preferences

Peacock Eels are burrowing fish, so providing a suitable substrate is essential. They prefer sandy or fine-grained substrates that allow them to dig and create burrows. Avoid using sharp or rough substrates that may injure their delicate bodies.

Lighting Requirements

Peacock Eels do not have any specific lighting requirements beyond providing a natural day-night cycle. Providing a regular lighting schedule of 8-12 hours of light per day is generally sufficient. Consider using low to moderate intensity lighting, as excessive brightness may cause stress or discomfort.

Decorations and Hiding Places

Creating a well-decorated aquarium with ample hiding places is important for Peacock Eels. They appreciate the presence of driftwood, rocks, caves, and dense vegetation, as these elements offer hiding spots and mimic their natural habitat. Ensure that the decorations are securely placed to prevent accidental collapses or injury.

Diet & Feeding

Type of Diet

Peacock Eels (Macrognathus siamensis) are primarily carnivorous fish. In the wild, they feed on a variety of small aquatic invertebrates, such as worms, insect larvae, small crustaceans, and other small prey.

Feeding Frequency

Peacock Eels should be fed once a day. It is recommended to feed them an amount of food that they can consume within a few minutes. Overfeeding should be avoided as it can lead to water quality issues and obesity.

Tips for Providing a Balanced and Varied Diet

To ensure a balanced and healthy diet for Peacock Eels, it is important to offer a variety of foods that mimic their natural feeding habits. Here are some tips:

  1. Live and Frozen Foods: Peacock Eels have a strong preference for live or frozen foods. Offer them small live or frozen prey, such as bloodworms, brine shrimp, daphnia, and small crustaceans. These provide essential nutrients and help satisfy their natural hunting instincts.
  2. Pellets and Tablets: Supplement their diet with high-quality sinking pellets or tablets formulated specifically for carnivorous fish. Ensure that the pellets are of an appropriate size for the eels to consume comfortably.
  3. Meaty Food Items: Provide occasional meaty treats like small pieces of shrimp, fish fillets, or even small strips of unseasoned cooked chicken. These can be offered as a supplement to their regular diet.
  4. Feeding Techniques: Since Peacock Eels are primarily bottom-dwellers, it’s beneficial to feed them near the substrate where they are most active. This allows them to easily locate and consume their food.
  5. Nutritional Variety: Varying their diet with a combination of live, frozen, and prepared foods helps ensure they receive a wide range of nutrients. This promotes overall health and reduces the risk of nutritional deficiencies.

Tank Mates

Compatible Species

Peacock Eels (Macrognathus siamensis) can coexist peacefully with a variety of non-aggressive community fish that are of similar size and temperament. Some compatible tank mates include:

  • Peaceful tetras, such as Neon Tetras (Paracheirodon innesi) or Ember Tetras (Hyphessobrycon amandae)
  • Peaceful gouramis, such as Dwarf Gouramis (Trichogaster lalius) or Honey Gouramis (Trichogaster chuna)
  • Larger peaceful cichlids, such as Angelfish (Pterophyllum scalare) or Keyhole Cichlids (Cleithracara maronii)
  • Rasboras, such as Harlequin Rasboras (Trigonostigma heteromorpha) or Chili Rasboras (Boraras brigittae)
  • Peaceful catfish, such as Corydoras species or Bristlenose Plecos (Ancistrus sp.)

It’s important to consider the size and potential behavior of tank mates to avoid any aggression or predation.

Incompatible or Potentially Problematic Species

Peacock Eels should not be kept with aggressive or fin-nipping species, as they have delicate fins that can be susceptible to damage. Avoid keeping them with:

  • Aggressive cichlids, such as African Cichlids or larger South American Cichlids known for their territorial behavior
  • Fin-nipping species like Tiger Barbs (Puntigrus tetrazona) or Serpae Tetras (Hyphessobrycon eques)
  • Predatory fish that may see the eels as potential prey, such as larger Cichlids or Pike Cichlids (Crenicichla sp.)

Recommendations for Creating a Harmonious Community Tank

To create a harmonious community tank with Peacock Eels, consider the following recommendations:

  1. Tank Size: Provide ample space and a tank of appropriate size to accommodate the potential tank mates and ensure territorial boundaries.
  2. Similar Temperament: Select peaceful fish species that are known for their compatibility and non-aggressive behavior.
  3. Size Compatibility: Ensure that the tank mates are of similar size to avoid potential predation or aggression based on size differences.
  4. Hiding Places: Create ample hiding spots and cover with decorations like driftwood, rocks, caves, or dense vegetation. This allows fish to establish territories and provides shelter for the Peacock Eels.
  5. Observation and Monitoring: Regularly observe the tank to ensure that all tank mates are getting along well. If any signs of aggression or stress are noticed, it may be necessary to rehome or rearrange the tank to maintain harmony.


Breeding Behavior

Breeding Peacock Eels (Macrognathus siamensis) in captivity can be challenging and rare. These fish have complex breeding behaviors that involve courtship rituals and specific conditions for successful reproduction. Males may engage in impressive displays to attract females, including spiraling movements and flaring their fins.

Ideal Breeding Conditions

To encourage breeding, replicate the following ideal conditions:

  1. Separate Breeding Tank: Prepare a separate breeding tank to provide the ideal environment for spawning. The tank should have similar water parameters to the main tank and be equipped with suitable hiding places, such as PVC pipes or caves, to simulate natural breeding sites.
  2. Water Parameters: Maintain the water temperature between 78-82°F (25-28°C), with a slightly acidic to neutral pH range of 6.5-7.5. Ensure excellent water quality and consider performing partial water changes before breeding attempts.
  3. Introduce Pairs: Place a compatible male and female Peacock Eel in the breeding tank. Monitor their behavior closely, as males may display territorial or aggressive behavior towards females during courtship.
  4. Spawning Behavior: Successful spawning may involve the male wrapping his body around the female while releasing sperm and eggs simultaneously. The adhesive eggs are usually scattered across plants, decorations, or the substrate.
  5. Egg Removal: After spawning, it’s advisable to transfer the eggs to a separate hatching tank or use a mesh barrier to protect them from being consumed by the adult fish.

Raising Fry and Specific Care Requirements

Raising Peacock Eel fry requires careful attention and specialized care. Consider the following guidelines:

  1. Optimal Water Conditions: Maintain excellent water quality with stable parameters to ensure the health and development of the fry. Perform regular water changes and provide a suitable filtration system.
  2. Larval Diet: Newly hatched fry will initially rely on tiny live foods, such as infusoria, freshly hatched brine shrimp, or commercially available liquid fry food. As they grow, you can gradually introduce larger live or frozen foods, finely crushed pellets, or powdered fry food.
  3. Tank Setup: Set up a separate rearing tank with appropriate hiding places, gentle water flow, and suitable food sources. Ensure that the tank is well-covered to prevent the fry from escaping.
  4. Growth and Development: Monitor the growth and development of the fry, ensuring they have access to proper nutrition and a safe environment. Frequent water testing and maintenance are crucial to their well-being.

Health & Disease

Peacock Eels (Macrognathus siamensis) can be susceptible to certain diseases. Understanding common diseases, their symptoms, and implementing preventive measures can help maintain their health. In case of illness, prompt treatment is essential.

Common Diseases and Their Symptoms

  1. Ich (Ichthyophthirius multifiliis): Symptoms include white spots resembling grains of salt on the fish’s body and fins, along with increased scratching or rubbing against objects.
  2. Fungal Infections: These can manifest as cotton-like growth on the fish’s body or fins, sometimes accompanied by frayed or decaying fins.
  3. Bacterial Infections: Symptoms may include open sores, ulcers, redness, inflammation, or abnormal growths on the fish’s body. Affected fish may also exhibit lethargy, loss of appetite, or rapid breathing.

Prevention and Treatment Strategies

To prevent diseases and promote the overall health of Peacock Eels, consider the following strategies:

  1. Quarantine New Fish: Before introducing new fish to the tank, quarantine them separately for a few weeks to observe for any signs of disease. This helps prevent the introduction of pathogens to the main tank.
  2. Maintain Optimal Water Quality: Proper water parameters, regular water changes, and effective filtration are crucial for maintaining good water quality. Avoid overstocking and monitor ammonia, nitrite, and nitrate levels.
  3. Balanced Diet: Provide a balanced and varied diet to support the fish’s immune system. Nutritional deficiencies can make fish more susceptible to diseases. High-quality commercial foods and occasional live or frozen foods can help ensure a well-rounded diet.
  4. Stress Reduction: Minimize stress factors such as sudden changes in water parameters, overcrowding, aggressive tankmates, or inadequate hiding places. A stressed fish is more prone to diseases.
  5. Prompt Treatment: If you notice any signs of illness, such as abnormal behavior, physical changes, or other symptoms, promptly isolate the affected fish and consult with an aquatic veterinarian or knowledgeable aquarium professional. They can recommend suitable treatment options, which may include medications, water adjustments, or supportive care.

Care Level

Difficulty of Care

Peacock Eels (Macrognathus siamensis) are considered to have an intermediate care level. While they are not recommended for complete beginners, they can be successfully kept by aquarists with some experience in fishkeeping.

Special Considerations or Requirements

When caring for Peacock Eels, it’s important to keep in mind the following considerations:

  1. Tank Size: Providing a sufficiently large aquarium is crucial to accommodate their size and activity level. A minimum tank size of 40 gallons (150 liters) is recommended.
  2. Burrowing Behavior: Peacock Eels are natural burrowers and appreciate the presence of suitable substrates and hiding places. Providing a sandy or fine-grained substrate and ample hiding spots, such as caves or driftwood, is essential to replicate their natural behavior.
  3. Water Quality and Parameters: Maintaining excellent water quality is vital for the health of Peacock Eels. Regular water changes, effective filtration, and monitoring of water parameters are necessary. Keeping the temperature between 75-82°F (24-28°C) and maintaining a slightly acidic to neutral pH range of 6.5-7.5 is recommended.
  4. Compatibility: Careful consideration of tank mates is important to ensure compatibility and prevent aggression or predation. Avoid keeping them with aggressive or fin-nipping species, as their delicate fins can be susceptible to damage.
  5. Feeding: Peacock Eels are primarily carnivorous and have a preference for live or frozen foods. Providing a varied and balanced diet is essential for their health and well-being.

Conservation Status

As of my knowledge cutoff in September 2021, the specific conservation status of the Peacock Eel (Macrognathus siamensis) according to the IUCN Red List was not available. It’s important to note that conservation statuses can change over time as new assessments are conducted.

However, it is generally recognized that the collection of wild-caught Peacock Eels for the aquarium trade can have an impact on their populations in their native habitats. Sustainable practices, such as captive breeding programs and responsible sourcing from reputable suppliers, can help alleviate pressure on wild populations.

Regarding legal restrictions on keeping the species in captivity, regulations may vary depending on the country or jurisdiction. It is advisable to consult local laws and regulations to ensure compliance with any restrictions or requirements related to keeping Peacock Eels in captivity. This may include obtaining necessary permits or adhering to specific guidelines for fishkeeping.

It’s important to promote responsible and ethical practices within the aquarium hobby to support the conservation of aquatic species and their habitats.

Additional Information & Fun Facts

Here are some interesting facts and trivia about Peacock Eels (Macrognathus siamensis):

  1. Unique Name: The common name “Peacock Eel” is derived from the fish’s vibrant and iridescent coloration, resembling the eye-catching feathers of a peacock’s tail.
  2. No True Eel: Despite the name, Peacock Eels are not true eels but rather part of the family Mastacembelidae, which includes various species commonly known as spiny eels.
  3. Burrowing Experts: Peacock Eels are known for their exceptional burrowing abilities. They use their elongated bodies and specialized snouts to create tunnels and hide among the substrate or decorations in the aquarium.
  4. Nocturnal Habits: These eels are primarily nocturnal, meaning they are most active during the nighttime. Observing their behavior during low-light conditions can offer fascinating insights into their natural habits.
  5. Air Breathability: Peacock Eels possess a labyrinth organ, a unique adaptation that allows them to breathe atmospheric air. This enables them to survive in low-oxygen environments or even make occasional trips to the water’s surface for a gulp of air.
  6. Long Lifespan: With proper care, Peacock Eels can live for an average of 8-10 years in captivity, providing long-lasting enjoyment to dedicated hobbyists.
  7. Quirky Personalities: Many hobbyists find Peacock Eels to have distinct and quirky personalities. They can display curious behavior, especially when exploring their surroundings or interacting with tank mates.

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