Freshwater Fish

Peacock Eel – Macrognathus siamensis: Care Guide

Peacock eels are unique freshwater fish that are also widely misunderstood. In fact, most aquarists don’t know much about them!

This guide will show you what you’re missing.

We cover care, tank mates, food, size, lifespan, behavior, and more. You’ll be eager to get one by the time you’re done reading!

Species Summary

The Peacock Eel (Macrognathus siamensis) is a unique aquatic creature that can add tons of biodiversity to your tank. These freshwater fish have many different names. You might see them called Siamese spiny eel, pointy-finned spiny eel, or even striped peacock eel.

Author’s Note: While all of those nicknames refer to these creatures as eels, technically they are not true eels! These tropical fish have elongated bodies like eels. However, they do not belong to the same family at all.

These fish come from nearly stagnant bodies of water in Southeast Asia. They are more frequent in the basins of the Mekong, Chao Phraya and Maeklong rivers.

In the fish farming community, Peacock Eels are a rare species that many aquarists dream of owning. While many find them challenging to care for, they are surprisingly manageable with a little knowledge!


The case of mistaken identity for this fish comes down to its appearance!

The peacock eel has a slender, elongated body with a pointed snout. But unlike a true eel, this fish has separate dorsal, anal, and caudal fins. The separation is subtle, which adds to the confusion!

Interestingly, the dorsal fin has sharp spines. They are difficult to see, but the spines can cause serious damage if care is not taken. Be careful when working in the tank or moving the fish with a net!

In terms of color, the peacock eel is usually tan or yellowish green. A brighter yellow defined line runs laterally from the snout to the caudal fin. It’s a vibrant accent that also accentuates the darker coloring.

Author’s Note: Towards the back of the fish, you’ll find three to six eyespots. These spots are dark black with a yellow or white perimeter. The spots are a form of mimicry that works to confuse would-be predators in the wild!

Life expectancy

These fish are a long-term investment. While there are no guarantees with life expectancy, the typical lifespan of the Peacock Eel is between eight and 18 years!

In general, pristine water conditions and a top-notch diet will help these fish live closer to the upper end of their life expectancy range. On the other hand, lackluster care will only increase your risks of illness and premature death.

Of course, genetics and luck also come into play. But the quality of care you provide will have a huge impact on the amount of time you have with your peacock eel.

Average size

These fish are quite large compared to conventional tropical species. The average size of a Peacock Eel is usually around 12 inches long!

Author’s Note: It’s worth noting that they will only reach that full size if they live in a larger aquarium. In general, captive peacock eels will top out at about nine inches.

Peacock Eel Care

Many assume that peacock eel care is difficult. While they certainly have their challenges, these freshwater fish aren’t as picky as you might think!

As long as you adhere to the care guidelines below, your fish should have no problem living a long and happy life.

tank size

The recommended peacock eel tank size is 40 gallons or larger. Some aquarists have had success with aquariums that hold as little as 20 gallons. However, we always recommend going bigger with a large fish like Peacock Eel.

A larger tank provides more room to roam (resulting in better enrichment). Plus, it gives fish more room to reach their true size potential.

water parameters

It is vital to prepare the underwater environment based on the needs of your Peacock Eel. The best course of action is to mimic its natural habitat as closely as possible.

Peacock eels are tropical freshwater fish that come from Southeast Asia. They live in slow-moving rivers that are usually dense with vegetation and animal life. Fortunately, these fish can tolerate a wide range of parameters.

  • Water temperature: 73°F to 82°F (below 29 degrees is ideal)
  • pH levels: 6.5 to 7.5 (aim for neutral)
  • Water hardness: 6 to 25 DH

Author’s Note: To monitor these water parameters, you need to invest in a reliable water testing kit for your aquarium. This will make it easier to monitor your tank’s health and make adjustments when needed.

decorating the tank

Proper peacock eel care should include creating optimal habitat. These fish have quirky personalities and needs that you need to plan for.

The most important thing is to have a thick layer of sand substrate. Peacock eels are burrowers that like to hide most of their body in riverbeds. Gravels, rocks and pebbles can damage the body of the fish.

Create a sandy bottom that is at least four inches deep.

Then add various hiding spots throughout the tank. Use plenty of decorative objects that your fish can slide on. Some good options include faux rock caves, driftwood, and PVC pipe.

Regardless of what you use, make sure there are no sharp edges that could harm the fish.

It is also a good idea to add plants. However, you may encounter some problems with unrooting.

If that happens, replant the vegetation in a spot where your peacock eel won’t go. Alternatively, you can use floating plants or silk plants anchored to the glass.

To keep the environment quiet, adjust the filter outlets to reduce the flow as much as possible. These fish do not like significant movement in the water.

Author’s Note: Top it all off with a secure lid. Peacock eels are notorious escape artists! Their slender bodies make it easy for them to get through tight spots. Not only that, but they are powerful jumpers.

Possible common diseases

Peacock eels are no more or less susceptible to disease than any other tropical freshwater fish. They can find all the usual health problems.

White spot disease (also known as Ich) is a common condition to watch out for. It is a parasitic ciliate that can quickly spread throughout a community tank. The disease causes white patches to form all over the body.

Although it is a deadly disease, it is also very treatable if caught early. Quarantine infected fish and provide over-the-counter medication to relieve symptoms.

Fungal infections are also a common problem with peacock eels. Fungal problems usually appear as wool-like growths on the fish’s skin, mouth, or gills. Like Ich, the infections can spread if you don’t provide treatment.

The good news is that many of the most prevalent aquatic diseases are preventable. with proper care and maintenance of the tank.

Check water conditions regularly. Test the temperature and pH levels to make sure the habitat is right for your peacock eel.

To avoid major problems, perform partial water changes every two to four weeks. Changes of 25 percent will keep ammonia and nitrate levels low.

Food and Diet

Peacock eels can be a bit finicky when it comes to food. In fact, it is one of the most difficult aspects of peacock eel care!

While most fish are more than eager to eat, that’s not the case with these creatures.

In the wild, they will emerge at night to find high-protein foods. A similar diet is better for living in captivity.

You can provide insect larvae, bloodworms, nocturnal reptiles, brine shrimp, and more. They will consume live, freeze-dried and frozen foods.

Direct feeding is the preferred method for many aquarists. Use a pipet or syringe to deliver the food directly to your fish. This ensures that they get the sustain they need before other tankmates can steal it.

Author’s Note: It may take some experimentation to find the right feeding schedule for your peacock eel. Most owners find that the fish only eat two or three times a week.

behavior and temperament

Contrary to popular belief, peacock eels are quite docile. They are quite shy compared to other popular tropical fish.

They prefer to spend their days relaxing in furs or burrowing under the substrate. You will see that the fish bury most of their body under the sand. The only exception is the head, which sticks out to look at the tank!

Author’s Note: Digging is a normal and healthy behavior, but these fish shouldn’t do it all the time. If your peacock eel spends all of its time on the substrate, it may be a sign that it doesn’t have enough fur in the tank for it to be comfortable with.

Don’t expect to see these fish during the day. They are primarily nocturnal and only emerge once the lights go out.

Peacock eels can get along with most fish. The only exception is other peacock eels.

They are known to become territorial against their own kind, so it is best to only have one Peacock Eel per tank.

Peacock Eel Tank Mates

Believe it or not, peacock eels are fantastic community fish! They are calm and like to stand their ground. As a result, you can host them with others without any problem.

Due to their size, small fish are best avoided. Despite their gentle nature, peacock eels treat small animals as food. Common community fish like Neon Tetras are out of the question. The same goes for snails, crabs and small invertebrates.

Stick with fish that are larger than the peacock eel’s mouth to keep the peace!

Some good tankmates for the Peacock Eel include:

  • Rainbowfish (we like Forktail)
  • rasboras
  • Swordfish
  • hatchet fish


Breeding peacock eels in captivity is very difficult. In fact, most would say that’s impossible in a closed environment like a home aquarium.

In the wild, these fish spawn during the rainy season when the environment is flooded. If a pair decides to breed, they will chase each other in a courtship display.

The females then lay sticky eggs on floating plants. After three or four days, the eggs hatch.

Some breeders theorize that providing a constant supply of fresh water to a closed environment could simulate flood conditions and trigger spawning. However, replicating those circumstances in an aquarium is nearly impossible. For this reason, breeders have not had much success with the peacock eel.

If a breakthrough in breeding strategy comes along, we’ll be sure to update this guide to include what others have had success with.

final thoughts

Peacock eel care is much easier than most aquarists realize. These fish are low maintenance, fairly peaceful, and a lot of fun to watch!

We hope that this guide has been useful to you and encourages you to give this species a chance. They are really very special!

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