Peacock Eel: Care, Tank Mates, Food, Size & Lifespan

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

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 for yourself 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 go by many different names. You might see them called the Siamese spiny eel, the spot-finned spiny eel, or even the striped peacock eel.

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

These fish come from near-stagnant bodies of water in Southeast Asia. They’re most prevalent in the Mekong, Chao Phraya, and Maeklong River Basins.

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In the fish-keeping community, peacock eels are an oddball species that many aquarists dream of owning. While many believe that they are challenging to care for, they’re surprisingly manageable with a little bit of know-how!


This fish’s case of mistaken identity comes down to its appearance! 

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

A peacock eel

Interestingly enough, the dorsal fin is sporting sharp spines. They are difficult to see, but the spines can do some severe damage if you’re not careful. Exercise caution whenever working in the tank or moving the fish with a net!

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

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


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

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

Of course, genetics and luck come into play as well. But the quality of care you provide will have a big impact on how much time you have with your peacock eel.

Average Size

These fish are quite big compared to conventional tropical species. The average peacock eel size is usually around 12 inches in length!

Author Note: It’s worth pointing out that they will only reach that full size if they live in a larger aquarium. Generally, captive peacock eels will max 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 demanding as you might think!

As long as you stick 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 more. Some aquarists have seen success in aquariums that hold as little as 20 gallons. However, we always recommend going bigger with a large fish like the peacock eel.

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

Water Parameters

It’s vital to prepare the underwater environment based on the needs of your peacock eel. The best course of action is to mimic their 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 in vegetation and animal life. Fortunately, these fish can tolerate a wide parameter range.

  • 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 Note: To monitor these water parameters you should invest in a reliable water test kit for your aquarium. This will make it easy to keep tabs on the health of your tank and make adjustments when needed.

Decorating The Tank

Proper peacock eel care has to include setting up an optimal habitat. These fish have quirky personalities and needs that you must plan for.

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

Create a sandy bottom that’s at least four inches deep.

Then, add several hiding spots throughout the tank. Use many decorative objects that your fish can slither into. Some good options include faux rock caves, driftwood, and PVC pipes.

Macrognathus siamensis

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

It’s also a good idea to add plants. However, you may encounter some issues with uprooting. 

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

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

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

Common Possible Diseases

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

White spot disease (also known as Ich) is a common condition to be wary of. It’s a parasitic ciliate that can quickly spread throughout a community tank. The disease causes white spots to form all of the body.

While it is a deadly disease, it’s also very treatable if caught early. Quarantine any infected fish and provide over-the-counter medicines to alleviate symptoms.

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

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

Monitor the water conditions regularly. Test the temperature and pH levels to ensure that the habitat is just right for your peacock eel.

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

Food & Diet

Peacock eels can be a little picky when it comes to food. In fact, it’s one of the more 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 best for life in captivity.

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

Targeted feeding is the preferred method for many aquarists. Use a pipette or syringe to deliver the food directly to your fish. This ensures that they’re getting the sustenance they need before other tank mates can steal it.

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

Behavior & Temperament

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

They prefer to spend their days relaxing in hides or burrowing beneath the substrate. You will see the fish bury most of their body under the sand. The only exception is the head, which pokes out to observe the tank!

Author Note: Burrowing is normal, healthy behavior, but these fish shouldn’t do it all of the time. If your peacock eel is spending all of their time in the substrate, it may be a sign that you don’t have enough hides in the tank to make them comfortable.

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

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

They’re known to get territorial against those of their own species, so it’s best only to have one peacock eel per tank.

Peacock Eel Tank Mates

Believe it or not, peacock eels make fantastic community fish! They’re easy-going and like to stick to themselves. As a result, you can house them with others without any issues.

Due to their size, it’s best to avoid small fish. Despite their gentle nature, peacock eels will 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 to fish that are larger than the peacock eel’s mouth to keep the peace!

Some good tank mates for the peacock eel include:


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

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

Females then lay sticky eggs onto floating plants. After three or four days, the eggs will hatch.

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

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

Closing Thoughts

Peacock eel care is a lot easier than most aquarists realize. These fish are pretty low-maintenance, quite peaceful, and a lot of fun to observe!

We hope this guide was helpful and encourages you to give this species a chance. They’re really quite special!

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