Peacock Eel Care Guide: Size, Diet, Lifespan & More | 2023

By: Martin McAdam
Updated: May 29, 2023

The Peacock Eel (Macrognathus siamensis) is a beautiful and unique fish popular among aquarium hobbyists. This eel has a long, slender body with bright colors that range from blue and green to purple and red. Peacock Eels can grow up to 1.2 feet long in the wild, but in an aquarium, they usually average around 10 inches long.

They make excellent additions to a home aquarium, but like all other fish, their needs must be met if the owner is to enjoy success in keeping them healthy and alive for a long time.

This article will teach you everything you need to know about caring for Peacock Eels so they can live long and happy lives in your home aquarium.

Peacock Eel: Species Summary

Common Name:Peacock Eel, Spotfin Spiny Eel, Peacock Julie, and Painted Julie.
Scientific Name:Macrognathus siamensis
Origin:Asia (Cambodia, Laos, Malaysia, Peninsular Thailand)
Size:Up to 1.2 feet long
Lifespan:Maximum 18 years
Tank size:30 gallons
Water Temperature:76° to 82° Fahrenheit
pH Range: 6.5 to 7.5
Care Level:Easy to Moderate

Peacock Eel taxonomy: From the Greek, "macro" meaning large, and "gnathic" meaning jaw; this fish is also known as the Giant Snake Eel, Spotted Snake Eel, Peacock Spiny Eel, and Big-mouthed Spiny Eel.

The Peacock Eel or "Macrognathus siamensis" is a long slender fish from Thailand. These fish are typically green to blue with black spots and red/purple highlights.

The fish can reach up to 1.2 feet in the wild and averages 10 inches in an aquarium. Like all eels, the peacock has no scales and instead has thick, smooth skin without any features such as fins or gills.

Since these fish are so unique looking, they have captured many hearts and minds in the aquarium hobby.

People enjoy watching these fish because of their exciting behavior and beautiful colors.

Peacock Eel: Appearance

Since the Peacock Eel is a relatively new addition to the aquarium hobby, little is known about its appearance. What has been observed is that they are typically green to blue with black spots and red and purple highlights, as mentioned earlier.

Peacock Eel Appearance

They have a long, slender body with no scales and thick, smooth skin. Peacock Eels also lack any fin or gill.

Peacock Eel: Size And Growth Rate

In the wild, Peacock Eels can grow up to 1.2 feet long. However, in an aquarium, they usually average around 10 inches long. This is because they are typically not as aggressive in captivity and do not need to compete for food or space.

Peacock Eels can grow too long in the wild but average around 10 inches in an aquarium. This makes them an excellent choice for smaller aquariums.

Peacock Eel: Lifespan

Unfortunately, not much is known about the lifespan of the. Some reports say Peacock Eel can live up to 10 years or more, while others report shorter lives. They will likely live around 5 to 8 years; some may even reach 10+.

They have a lifespan of 18 years in the wild. They can live just as long in an aquarium with the proper care and maintenance.

Peacock Eel: Behavior

Peacock Eels are a unique and exciting sight to see in an aquarium. They often move around by crawling and can be pretty fast at times. If they feel threatened, they bury themselves into the gravel or substrate so that their entire bodies are covered except for their eyes. These fish also have fascinating feeding habits.

Peacock Eel Behavior

They are very active fish and can often be seen swimming around their aquarium. They are known for being curious and will investigate anything that comes into their territory. They are also quite boisterous and often compete with other fish for food.

Peacock Eel: Temperament

Peacock Eels are not aggressive fish but can be territorial and aggressive toward other fish that share their space. If you plan on keeping more than one Eel in your aquarium, ensure they are introduced to the aquarium simultaneously.

Peacock Eels are nocturnal. You will not see your fish often or for long periods, so don't be alarmed if you only see them occasionally throughout the day. When they leave their hiding spots, they explore their surroundings and may even come up to the edge of the aquarium to see what's going on.

Peacock Eel: Habitat

The Peacock Eel is a tropical fish and an excellent addition to a warm freshwater aquarium. The temperature range for this fish is 76° to 82° Fahrenheit, and the pH should be between 6.5 to 7.5, which matches that of most tap water.

This fish must be kept in soft or slightly acidic water. However, it can adapt to harder conditions if necessary. If you plan on keeping these eels in a closed aquarium, you must have an efficient filtration system that does not produce large amounts of waste for the peacock to eat.

This will help significantly reduce the need for water changes.

Aquariums can range from small 10 gallon tanks to huge 200-gallon tanks. As long as the tank is adequately filtrated and heated, the size doesn't matter. They can do well in densely planted aquaria and those with little to no plants. Remember that these fish are mostly Omnivorous.

Peacock Eel: Breeding

Peacock Eels have not been bred in captivity very often, so there is not much information on how to do it. They are believed to be egg layers, and the eggs are deposited on the substrate. There is no information on whether or not they are cannibalistic, so it is best to avoid keeping them together if you are trying to breed them.

Peacock Eel: Food & Diet

The Peacock Eel has no teeth but a firm suction mouth to grasp its prey. It then bites down and swallows the prey whole. In the wild, Peacock Eels are Omnivorous and eat a variety of small invertebrates, such as larvae, crustaceans, insects, and worms.

In an aquarium, they can be fed various foods, including frozen bloodworms, brine shrimp, tubifex worms, and krill. Providing them with occasional live food such as earthworms, freshwater shrimp, and feeder fish is also important.

Peacock Eel: Care

Peacock Eels are not difficult to care for, but some things must be kept in mind to keep them healthy and happy.

Peacock Eel Care

Tank Size

Aquariums of at least 40 gallons are recommended for Peacock Eels. This gives them enough space to swim around and explore. Remember that they are active fish and need plenty of room to move.

Little is known about how big they can grow when they are a relatively new addition to the aquarium hobby. Most hobbyists keep them in tanks around 18 to 24 inches long and 8 to 10 gallons in size.

Water Conditions

These fish are susceptible to water conditions and must be kept in soft, slightly acidic water. These fish will not survive any significant change in pH or hardness, so ensure your tap water is close enough to these levels before adding it to the aquarium.

If you plan on keeping the eel in a closed aquarium system, ensure you have a very efficient filtration system that does not produce large amounts of waste. This is for the benefit of both you and your fish since water quality will be better, and it will reduce the need to perform frequent water changes.

Peacock Eels, like many other fish, do best when they are kept in groups; however, due to their size, they should only be kept in groups of 3 or more. Another thing to remember is that they are used to living in brackish waters, so you should create similar conditions for them.

This means that they need tanks that have both fresh and saltwater components. The best way to do this is to have a tank with a section of fresh water and saltwater. You can also use a marine aquarium salt mix to create brackish water conditions.

Water Temperature

The Peacock Eel can tolerate a temperature range of 76° to 82° Fahrenheit. However, keeping the tank at 74° to 80° is recommended since this is the ideal temperature for most tropical fish.

pH Level

The Peacock Eel can tolerate a pH range of 6.5-7.5, but keeping the pH at 6.5-7.0 is recommended for the best results.


They do not need special lighting and can thrive in various lighting conditions. However, providing a moderate lighting level is generally recommended so that the aquarium inhabitants can thrive.


They do not need fine gravel and can thrive in various gravel conditions. However, it is generally recommended to use fine gravel that will not damage their delicate skin.


They do not have scales; they are very susceptible to bacteria and other contaminants in the water. For this reason, it is essential to use a good quality filter when keeping them in an aquarium. A filter that can turn over the water at least 5 times per hour is ideal.


They can tolerate a temperature range of 76° to 82° Fahrenheit; using a heater in their tank is unnecessary. However, if the aquarium is kept in a room below 72 degrees, a heater may be necessary to keep the water at an acceptable temperature.

Decorating The Tank

When decorating the tank, it is essential to use items that will not harm the delicate skin. Some good options include silk plants, artificial rocks, and driftwood. Ensure that any metal ornaments are kept from the tank as they can rust and release toxins into the water.

They will spend most of its time hiding in an aquarium. Providing them with plenty of places to hide to feel secure in their environment is important. Some good options for hiding places include PVC pipe cut into 4" pieces, artificial plants, ceramic flowerpots, and plastic caves.

Peacock Eels are nocturnal and will spend most of the day asleep. Also, their metabolism is prolonged during this time, and these fish will need little to eat. It is not uncommon for a Peacock Eel to go several months without eating in an aquarium setting.

The only times that you should see the eel out and about is during feeding time or when it is very agitated. Under normal circumstances, they should be considered shy fish and usually only come out when they feel safe.

Peacock Eel: Common Possible Diseases

The most common disease that plagues Peacock Eels is a bacterial infection. These can be caused by poor water quality, physical wounds, or injuries sustained by tank mates. The marks that you see on the body of your eel are probably scars leftover from past hurts and not something dangerous like ich.

The only other common disease that plagues this species is neurological ich (NSP). Symptoms include dark marks on the skin, raised scales, and quick darting movements.

It is important not to confuse NSP with normal behavior or fish rubbing themselves against decorations in the tank. If you suspect your eel has NSP, treat it with an anti-parasitic medication.

Peacock Eel: Treatment For Diseases

Treating wounds or injuries that your Peacock Eel sustains promptly is important to prevent infections.

When treating a sick Peacock Eel, it is essential to move slowly and not try to treat your fish with the first medication you come across. Many drugs on the market are made for saltwater fish and can be toxic to freshwater species such as Peacock Eels.

If you suspect that your fish has a bacterial infection, then there are a few different medications that you can try. One option is erythromycin, which can be purchased from most pet stores. Another option is ampicillin, a prescription-only drug that can be obtained from a veterinarian.

If the eel has contracted NSP, it must be treated with an anti-parasitic medication. Another option is to move the eel to the main tank for a few months and treat it there using an anti-parasitic drug, such as Praziquantel.

Peacock Eel: Tank Mates

Peacock Eels will not do well with aggressive fish and should be kept from them. If you plan on keeping this species with other fish, ensure the other fish are large enough not to become a snack. These eels do best when they have their tank or a tank.

Peacock Eels are not difficult to care for, but they have specific needs that must be met for a healthy and happy eel. If the proper steps are taken when purchasing your eel and setting up your aquarium, you should have no problem keeping these beautiful creatures.

Advantages Of Having Peacock Eel In Your Tank

  • Beautiful: The Peacock Eel is considered by many to be the second most beautiful fish in the world. As its name implies, the Peacock Eel has a colorful body that will lighten up your aquarium and bring an elegant flair into your home. It's not difficult to see how these eels got their name, as they are a sight to behold.
  • Interesting Behavior: Not only are Peacock Eels beautiful, but they are also exciting to watch. These eels are always on the move and can be seen swimming around their tank for food or hiding among the plants. They often come out during feeding time to snatch a bite of food and then quickly hide again.
  • Easy To Care For: Peacock Eels are one of the easier fish to care for and do not require much special attention. They will be content and thrive in their home aquarium if their basic needs are met.
  • Good With Other Fish: As mentioned earlier, Peacock Eels do not make good tank mates with other fish since they can very easily become food. However, if the aquarium is large enough and there are no aggressive fish in the tank, Peacock Eels can be kept with other species, such as loaches, catfish, and bottom feeders.
  • Low Maintenance: Besides being easy to care for, Peacock Eels are also low-maintenance fish. They do not require frequent water changes and can tolerate various water conditions.
  • Peaceful: Unlike other eel species, Peacock Eels are peaceful fish and will not attack or harm other fish in the tank.
  • Cute: Just look at them! How could you not think they are the cutest things in the world? This rule always has exceptions, but generally speaking, eels are adorable fish.
  • Long-Lived: The average life span of a Peacock Eel is about 13 years, which is around twice as long as most other fish.

Disadvantages Of Having Peacock Eel In Your Tank

  • Size: The more significant the aquarium, the better because Peacock Eels can grow up to two feet long and need much space in their tank. If you plan on having one of these beautiful fish, be prepared to give it plenty of room because its large size can quickly take over an aquarium smaller than 75 gallons.
  • Aggressive: Peacock Eels have a unique defense mechanism if they feel threatened in any way: to wrap their body around the nearest object and then push their long sharp teeth into it until it bleeds.
  • When this happens, a poisonous substance is released from its mouth and poisons the area so badly that most prey will die. Because of this, Peacock Eels should never be housed with other fish in an aquarium since they can quickly become the victim of an attack.
  • Price: Another disadvantage of keeping Peacock Eels is their high price tag. These fish can cost anywhere from $25-$50, making them one of the most expensive freshwater fish.
  • Diet: Peacock Eels are carnivorous and only eat meat, so they should not be fed with other fish in their tank. This can cause problems because if this species isn't given enough food, it may begin to nip at the fins of other fish in the aquarium, leading to infection or even death.
  • Temperament: While Peacock Eels are less aggressive than other eel species, they can still be temperamental. If they are not getting the food they need or feel threatened, they may become agitated and swim around erratically in their tank.
  • Not A Good First Eel: Peacock Eels are not good first eels as they can be challenging to care for and need a lot of space in the aquarium. If you want to keep an eel as a pet, we recommend trying out more minor, less aggressive species such as yellow spotted or snowflake moray eels.
  • Food: Peacock Eels like to eat live food, which can be difficult for some people to provide. They primarily feed on live fish but eat shrimp and crabs if available in the tank. Sometimes Peacock Eels will refuse food until they become accustomed to their home aquarium so, it is important not.


The Peacock Eel is a beautiful species that can make an excellent addition to any aquarium. These fish are best kept in tanks or with other large, non-aggressive fish. They are easy to care for and do not require a lot of special attention. Peacock Eels should never be fed with other fish in their tank as they will become aggressive and may even kill their prey.

So, if you are thinking of adding a Peacock Eel to your freshwater aquarium, remember the above information. These fish are beautiful, interesting, and easy to care for but they do have their own set of specific needs that must be met. With a little bit of preparation, you can ensure that your Peacock Eel enjoys a long and healthy life in its new home.

Disclaimer does not intend to provide veterinary advice. We go to great lengths to help users better understand their aquatic friends. However, the content on this blog is not a substitute for veterinary guidance. For more information, please read our disclaimer.

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