Home » Fish Guides » Peacock Eel (Macrognathus siamensis) | 12 Colorful Facts |

Peacock Eel (Macrognathus siamensis) | 12 Colorful Facts |

Peacock eel is a unique type of fish that needs specific care in order to thrive.

Many aquarists love to keep these fish due to their handsome look with six attractive “eyespots” that resemble peacocks.

However, most of them think twice before buying these fish as they think that Peacock eels are hard to keep.

But, the truth is, they are easy to care of if you know their demands. This guide teaches you the specific needs of Peacock eels so that you can raise a them successfully in your aquarium.

Peacock Eel

What is Peacock Eel?

Peacock eel (Macrognathus siamensis) is a spiny eel fish belonging to the Mastacembelidae family.

It is popular for its ornamental appearance that it is widely used in aquariums.

This fish has a brownish elongated body with six dark spots resembling peacocks. These dark spots often help these fish to camouflage and confuse the predators.

Its tail fin stretches all along the length of its body and stops just before its head. The upper body of these fish is covered with spikes to defend against predators.

A thin pale yellow stripe runs from the eye to the tail fin, providing a subtle darker patterning.

Although they have an elongated body, it is rather thick. Peacock eels also have a unique pointed snout.

They are nocturnal species found in Southeast Asia. They are native to Thailand, Malaysia, India, and Sri Lanka, where they can be found in slow-moving and densely vegetated streams, marshes, and ponds. 

Peacock eels usually hide under rocks during the daytime. But at night time, these fish actively feed on small fish, crabs, and worms.

These nocturnal fish are rarely seen in the wild due to their natural hiding habit during the daytime.

They are not known to breed in captivity. Therefore, the specimens available on the trade are often wild-caught ones.

These fish are ubiquitous in their natural habitats. Consequently, they are listed as Least Concern in the IUCN Red List.

How big do Peacock Eel get?

In the wild, they grow up to 15 inches long. However, they tend to grow up to 12 inches in captivity.

Is Peacock Eel aggressive?

Unlike many other spiny eels, Peacock eels are peaceful and shy.

These docile species get intimidated when they get in touch with large and active species like Oscars or Silver dollars. So, it is better to keep these fish with other passive species of similar size.

Since these are carnivore fish, they can be aggressive toward small fish, shrimps, crabs, and snails. But, overall, they are non-aggressive fish species.

Peacock Eel behavior

They are generally peaceful and shy fish that tend to ignore other fish around. Because of this nature, you can house them with any large-sized fish kept at community tanks.

Peacock eels are also peaceful with their own kind but prefer to stay in solitary as they are territorial.

When you first introduce these fish to your aquarium, they will ignore eating because of their shy nature. But, once they are settled in, they will accept food slowly over time.

Peacock eels are bottom dwellers. Although they get along well with tank mates, it’s better not to have catfish and loaches when you introduce these fish to your aquarium.

Catfish and loaches are known to eat too quickly, which will make your aquarium eel uncomfortable in the first few days.

In the wild,they are nocturnal species. They will be active at night time and hide during the day. So, you must provide them with good hiding places like driftwood, caves, or plants to reduce stress.

How long do Peacock Eels live?

As for the lifespan, they lives around 8-18 years under the proper care.

One look care guide

Scientific nameMacrognathus siamensis
Common namePeacock eel
Spot-Finned Spiny Eel
Peacock Spiny Eel
Siamese Spiny Eel
Striped Peacock Eel
Spotfinned Spiny Eel
Care levelIntermediate
Native toThailand
Sri Lanka
Type Freshwater bottom-dwelling fish
Color Brownish with six dark spots
Tank size35 gallons minimum
Preferred temperature73 – 82 degrees Fahrenheit (22.8 -27.8 degrees Celsius)
Other water parameters (ammonia, etc.)Hardness : 6 – 25 dGH
pH level : 6 to 8
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: 0 ppm
Preferred salinityNo salinity
Size15 inches in the wild, 12 inches in captivity
Life span8 to 18 years
Temperament Peaceful
Recommended tank matesRelatively large peaceful fish
Preferred foodCarnivore
Small fish
Feeding frequencyA couple of times per week
BreedingUnknown in the home aquaria, egg layers

Peacock Eel care

They are relatively easy to take care of if you know what they need. They may not be suitable for beginner aquarists who have little experience with keeping fish.

They need specific requirements in order to thrive in your aquarium.

Peacock Eel size

They reach a length of up to 15 inches in the wild. In captivity, they tend to be 12 inches long maximum.

Peacock Eel tank size

They are bottom-dwelling fish that have low activity levels. Therefore they can manage to live in a small tank of about 35 gallons.

But, larger tanks with more water volume will be beneficial for your tropical fish. However, if you have a smaller specimen, you can house it in a 20-gallon tank of about 24 inches long.

How many Peacock eels should be kept together?

If you have plenty of space in your aquarium, you can have more than one fish in one tank.

However, make sure that each Eel has enough space to establish its territory. Otherwise, they may be aggressive toward each other.

The recommended number for one fish tank is only one Eel. This way, your fish can establish its territory freely and stay peacefully without any nuisance.

Tank setup

As Peacock eels are bottom-dwelling fish, the setting up of the tank includes lots of bottom decorations. 


They are known to burrow under the substrate. Therefore, you should provide a soft and smooth substrate to prevent injuries. Soft sand is best, but you can use soft gravel as well.


As these fish are shy and stay hidden most of the time, we should provide plenty of hiding places like driftwood, rocks, caves, and plants.

You can also use PVC tubes as caves. Make sure that all these objects are stable enough to hold your Eel’s weight.

Do not use any sharp objects like rocks or shells. Sharp objects can cause injuries to your fish by digging its scales.


Peacock eels are known to be plant-friendly. So you can add live plants to your tank. They will not damage the plants.

However, they may uproot the plants. So, you should place them firmly at the bottom.


Peacock eels are nocturnal fish species, so they prefer dim light at night time. They will be active at night, so you should dim the lights before turning them off.

Filtration and other equipment

Peacock eels do best in well-oxigenated water with good water movements. Therefore, you should provide an efficient filtration system with a pump.

You can add a powerhead or filter sponge to keep the water flow going.

Tank lid

Peacock eels are known to be escape artists. Make sure you seal the lid very well before introducing your fish to its new home.

Water quality condition

Peacock eels require pristine water quality in order to thrive. Good water quality will ensure that your fish can live long and stay healthy.

They can survive in soft to medium-hard water in the range of 6 – 25 dGH.

Peacock eels are compatible with a wide range of pH levels. However, the recommended pH level is between 6.0 and 8.0. These are pure freshwater species, so they can not survive in brackish waters.

During cold seasons, you should provide a heater. The recommended temperate is between 73 – 82 degrees Fahrenheit (22.8 -27.8 degrees Celsius).

As these fish require clean water conditions at all times, frequent water changes are necessary.

You will have to change about 30% of the water each week. When performing water changes, be sure to vacuum excess food and wastes in the substrate.

Peacock eels require good water movement to thrive well. Provide a water turnover rate of around 10-15 times per hour. And also, make sure that the water flows down the tank walls where the Eel can feel it.

Peacock Eel breeding 

Peacock Eel male or female identification

These fish do not show sexual dimorphism. Therefore, it is impossible to differentiate a male from a female.

Identify pregnant Peacock Eel and their pregnancy stages

Peacock eels are egg-laying fish. Therefore, you can notice a gravid spot on your fish. This spot will be dark brown to black in color.

However, this will not be an easy task because you can not tell if your fish is male or female.

Peacock Eel breeding

Peacock eels have not been bred in captivity. The reason is as we believe because most peacock eels are kept singly in home aquaria.

Further, it isn’t easy to differentiate males from females. So, breeders can not find breeding pairs to breed in captivity.

Experts believe that Peacock eels also have the same breeding process similar to other Spiny eels.

And also, they believe that simulating flood season in captivity stimulates the breeding behavior of Peacock eels.

If you own more than one Peacock eel in your home aquarium, you can try breeding them by conditioning them.

Feed more high-quality food than the usual amount and provide an influx of clean water.

You can simulate the flood season by reducing the water level for about two weeks and gradually increasing the water level over a few weeks.

When filling up the tank, use cold water to simulate rainy water. The “cold water” shouldn’t be too “cold” as too cold water may inflict shock into your fish.

When your fish are ready to spawn, they will engage in courtship behavior. They will chase each other and swim in circles for several hours. 

Peacock eels spawn above floating plants and deposit their eggs among them. These eggs are sticky and will attach to the surface of plants.

These eggs will hatch after 3 to 4 days. The peacock eel fry will be free-swimming a few days after hatching and can start feeding after three days.

When you are using a separate tank for fry, filtering the water is very important. You need to have a cooling filter that will reduce the water temperature to about 78 F (26 C).

How many babies does Peacock Eel have?

As there are only a few documented cases of Spiny eel breeding in captivity, it is difficult to tell how many eggs do these fish lay. So, the amount of fish fry we will get is still a mystery.

Peacock Eel fry care

Peacock eel eggs take 3 to 4 days to hatch and a few more days for the fry to become free-swimming. Free-swimming fry can feed themselves.

Therefore you should feed them with nauplii in their first few days of life.

The fry is challenging to raise since they are prone to fungal infections. The usage of a fungus-based antifungal treatment may be helpful along with regular water changes.

You can buy these antifungal medications from your local aquarium supply store.

Special tips

These fish are sensitive to changes, so when you introduce them to your aquarium, they will stay hidden most of the time and avoid eating.

It will take several days to get over their shyness, and feeding them can be a challenge.

Therefore, you can try adding live small fish that are small enough for your fish to eat in the first few days.

This way, they may hunt the fish when they are hungry so that they don’t starve.

Peacock eels are very sensitive to water changes and medications. So, be extremely careful when changing water and when using medications. Especially, do not use copper-based medications with these fish.

How to feed Peacock Eel?

Peacock eels are carnivore species. Peacock eels are nocturnal, so they feed at night. They eat small fish, crustaceans, and worms.

So you can provide them with brine shrimp, prawns, and small fish.

To attract their attention, you can use a feeding stick. You can also feed them live ghost shrimp or live baby guppies.

Like any other spiny eel, peacock eels also prefer live and fresh food. So, it is essential to feed them with live and fresh food like brine shrimp, blackworms, bloodworms, and earthworms.

You can train some spiny eels to eat frozen and freeze-dried food like brine shrimp and bloodworms. But this may not work with most fish.

You should feed these fish after lights are turned off because Peacock eels prefer to feed at night.

They do not eat much. So, feeding them a couple of times per week is more than enough.

Some peacock eels even refuse to eat food most of the time. These specimens often eat once every two to three weeks. So, if your Peacock eel doesn’t eat much, do not worry as that is their nature.

Peacock Eel tank mates?

Peacock eels are generally peaceful fish that can get along well with other similar-sized fish.

This includes similar-sized fish of their own species as long as they get enough space to establish their own territory. They are perfect for keeping in tanks with medium to large-sized fish.

You will not be able to house these fish with smaller fish like guppies, tetras, and mollies as Spiny eels prey on them. They are not suitable for shrimp and snail tanks as well.

Since these are shy fish, it is not wise to house them with aggressive and semi-aggressive fish. As they are mostly defenseless, aggressive fish may injure your Peacock eel.

It is not wise to house bottom-feeder fish like catfish and loaches by the time you introduce your Peacock eel to your aquarium.

Because of their quickly eating behavior, your Peacock eel will refuse to eat at all when kept with these fish.

Therefore, introducing bottom feeder fish should be done carefully and gradually over time.

Some of the best tankmates include rasboras, hatchet fish, gouramis, rainbowfish, and swordtails.

Peacock Eel Problems and Diseases

Like any other Eel, Peacock Eels are prone to parasites and fungal diseases. It is essential to watch out for signs of illness. Some common problems and illnesses of Peacock Eels are,

Ick (Ichthyophthirius)

Peacock eels are very susceptible to Ick. Although Ick is common in all freshwater fish, eels will be the first ones to be attacked.

The problem with peacock eels is that they are susceptible to medications as well. You can not use copper-based drugs, and also you should use half of the dosage of the medicines for these fish. You can treat them by using reef-safe medications as well.

Fungal Diseases

These fish have very delicate skin with very small scales. Because of that, they get attacked by fungal diseases frequently.

Therefore, keeping clean water conditions is essential with these fish. This is one of the main reasons Peacock eels are not beginner-friendly.

Difficulty in Fish Handling

As their skin is delicate, handling these fish is difficult than other fishes. You have to be careful when netting these fish as it may injure these fish easily.

As you know, injuries can make these fish prone to bacterial and fungal infections.

They are sensitive to water changes

Keeping stable water conditions is often hard for a beginner aquarist due to the lack of knowledge.

But, if you keep Peacock eels, you must ensure that your tank has stable water conditions without fluctuations as these fish are sensitive to water changes.

Low water temperatures and changes in water chemistry can cause stress in these fish, making them prone to more diseases.

The key to keeping a healthy Peacock eel in your aquarium is providing pristine water conditions in your tank.

These fish are often hard to keep because of their vulnerability to diseases. Therefore, before you introduce any fish, decorations, or other equipment to your aquarium, you should quarantine them and properly clean them to ensure they are disease-free.

If given a disease-free environment with a high-quality diet, your fish can live a long life in your aquarium.

Related Questions 

Are Peacock Eels rare?

Peacock eels are not rare, but they are not commonly found in the aquarium trade. However, you can find these fish easily online, and they are reasonably priced.

How long does a Peacock Eel live?

Despite the fact they are challenging to care for, they can live as long as 18 years when given proper care.

Do Peacock Eels bite?

These fish are timid, and they will not eat anything that comes close to them. Therefore, they do not tend to bite.

Credit to : Myaquariuminfo
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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.