Freshwater Eels – A Complete Guide (Care, Diet, Facts)

When it comes to hobbyist aquariums, there are some pretty standard fish to include.  Common beginner freshwater fish are goldfish, guppies, bettas, and neon tetras.  But what about including a not so common fish to your tank?

That is where freshwater eels come in.  Freshwater eels provide a new visual impact when viewing your aquarium.  They come in a variety of species with a range of colors and sizes.

As with other aquarium fish, they need specific care and environments to live in.  You can’t throw them in a tank and call it good.  Don’t worry though, eels are easy to incorporate into your freshwater aquarium.

Types of Freshwater Eels

Tire Track Eel

Its name comes from the distinct markings covering most of its body.  This eel is quite common and not very aggressive.  It can grow to 28 inches, you will need a large capacity tank.

Zig Zag Eel

The Zig Zag Eel has similar markings to the Tire Track Eel but more so on the upper half of its body.  It grows to about 35 inches in length and live up to 18 years.

Black Spotted Eel

This eel gets its name from the black spots covering its body.  They too live upwards of 18 years and get about 20 inches in length.  Black Spotted Eels are friendly but shy creatures.

Peacock Eel

This small species grows to be only 11 inches, so it makes a great addition to smaller aquariums.  The name comes from the markings that run along the dorsal fin.  These resemble the plumage of a peacock.

Half-banded Spiny Eel

This is the smallest eel on this list maxing out at 8 inches.  A 10 gallon tank offers enough space to move around for them.  They live well with other fish, as long as the eel can’t swallow them.

Pink Paddletail Eel

The Pink Paddletail is one of the more rare and exotic eel species for aquarium use.  It prefers to stay buried under fine sand, rarely leaving its hiding place.

This eel grows to be 17 inches in length and can be quite skinny giving it the nickname ‘purple spaghetti eel’.  It has an attractive rose toned skin with some purple hues.

Fire Eel

Fire eels living in captivity grow to be around 32 inches.  This eel has dark grey or black skin with red and yellow stripes resembling flame decals on hotrods.

Electric Eel

This may be the most common eel that comes to mind due to its many Hollywood appearances.  This dark grey creature can grow to be 8 feet long, and has a lifespan of about 15 years.

This eel can produce large amounts of electrical energy, upwards of 600 volts.  Multiple shocks can cause respiratory and heart failure.   It is not recommended for beginner hobbyists.

Typical Eel Behaviors

More often than not, you will find your eel near the bottom of the aquarium.  It will spend most of its time keeping to itself, nestled away, watching its surroundings.

Some species are shy, opting to spend most of their time buried in the substrate or hiding in the plants.  Others will appear more active, swimming around the rocks or tank decorations.

Eels can be peaceful creatures if in a single species tank, or if their tank mates are larger than them.  If put with smaller aquatic creatures, you may find that some start to go missing.

If you have more than one eel in your aquarium, depending on species, you may find an “eel pit” develop.  This is a place where a group of eels will live or sleep together.  Usually a hole, pit, or crevice.

Most eels are nocturnal by nature.  This means they become more active at night.  This is usually when they would start hunting.  They have poor eyesight so they rely more on smell and other senses.

Like most animals, they can become accustomed to daily routines.  If you keep a set feeding schedule, you may find your new friend ready and waiting for you.

Some eels, like the Peacock Eel, are very good at escaping their tank.  In the wild, eels are known for being able to access difficult to reach areas.  Keep an eye on them during feeding time and tank maintenance.

The Aquarium

Each eel species has a natural habitat that it thrives in.  With your aquarium, you will want to replicate that environment as much as possible.  Doing so without disrupting your other aquarium inhabitants, if you have them.

In your research and planning, make sure to consider your eel’s specific preferences.  This includes water temperature and pH, hours of daylight, vegetation, and hiding spots.

Tank Size

The size of the aquarium tank you choose will depend on the eel species you buy.  Smaller species do not need as much room as the larger ones.

As a general rule, a 30 gallon tank is the smallest recommended size to use.  This ensures the eel, or eels, have plenty of room to move around.  Eel can become more aggressive if they feel cramped.

You will want to research the eel you want before buying it.  Find out how big it will grow so you can buy the appropriate size tank.

For tanks with multiple eels, follow these rules.  Tanks with smaller eels, around 15 inches, should have one eel to 10 gallons of water.  Tanks with larger eels, around 25 inches, should have one eel to 20 gallons of water.

If you bought an electric eel, please know that these fish breathe air.  They will need to come up for air every ten minutes.  Leave about 6 inches between the top of the water and the top of the tank.

Habitat Setup

The aquarium habitat should have all the following elements to make your eel feel at home.  There is room for variations so your tank will still have a custom look.

First, the substrate.  The substrate is the material that covers the tank floor.  Coarse sand and fine gravel allow eels to burrow and for live plants to spread their roots.

Second is live plants.  Live plants help to oxygenate the water and are very helpful if your eel prefers slow moving water.  Plants also provide eels with an alternative to burrowing.

Consider purchasing an aquascaping kit to care for the live plants in your tank.  Kits come with long tweezers and long scissors to help feed and trim the plants without getting bit.

Third are tank decorations.  Choose items that your eel friend can interact with.  A hollow log or skull are good options.  Also consider creating rocky outcrops or “shelves” for the eel to hide in and under.

Always be sure to clean any tank decor before placing it in an active aquarium.  They can carry contaminates and parasites that are harmful to your fish.

Next is lighting.  An eel’s natural habitat experiences between 10-14 hours of daylight.  You should mimic this using an LED light in the 6500K range on a timer system.

The water filtration device is the most important part of the aquarium.  Mechanical filtration removes debris from the water.  Biological filtration uses good bacteria to breakdown toxins in the water.

Lastly is the water itself.  The water temperature should be between 72 and 82 degrees Fahrenheit.  Use a water test kit to keep the dissolved oxygen level >5mg/L, ammonia level <0.05-0.1mg/L, and nitrite level <30mg/L.

Also watch the water pH level.  If the pH is too high or too low, your eel will become susceptible to illness.  Each eel has a preferred pH level range, so make sure to research your specific eel species.

An Eel’s Diet

Almost all eel species are omnivores.  But normal fish food, aka fish flakes, will not be enough for your eel.  You will need meat, and there are a variety of options for you to choose from.

Eels are hunters by nature and will prey on fish smaller than itself, preferably ones it can swallow.  They will generally leave similar sized or bigger fish alone.  Live feeder fish are a great way to keep your eel active.

Shrimp and other small crustaceans are great as well.  These can be fed as frozen or live food.  Ghost shrimp, brine shrimp, algae eating shrimp, and fiddler crabs are a few types to get you started.

Bloodworms and Tubifex worms offer good protein.  Sinking pellets are also a useful supplement to their diet.  These offer rich nutrients without having to worry about parasites or bacteria.  Try to keep some variety in your eel’s diet each week.

Teeth play a role in what your eel can eat.  Blunt teeth, like those on the Snowflake Eel, help with eating creatures with shells.  Sharp pointed teeth, like on a Moray Eel, are for catching and holding more slippery prey.

Other less obvious food choices include small frogs, pieces of beef heart, and squid.  These all provide quality protein and nutrients.

Not all eels can eat the same food though.  Do proper research on your specific eel before feeding.  Take into account the eel’s size, teeth, and prey from its natural habitat.

Caring for Your Eel’s Health

The best way to care for your eel is by doing routine maintenance on their tank.  You want to keep the tank in the same condition as when it was first set up.

Every day you should check the water temperature and that all equipment is working.  A filter or heater malfunction can have a negative effect on everything in the tank.

Perform a water quality test each week.  Your local pet shop will either sell you a kit or may offer free water testing.  Keep the O2, nitrate, ammonia, and pH levels within the proper range for your eel.

Change the water every 2 to 4 weeks, or as needed.  Plan to change 20% to 30% of the water each time.  The amount of live plants and fish count contribute to how often the water needs changing.

New water should match the temperature of the remaining tank water.  Pretreat the water as needed to remove any chemicals and ensure proper pH level.

In general, eels are more susceptible to diseases than other fish.  These include a variety of bacterial and fungal illnesses.

Fungal infections include gill rot, which shows up in gray patches under the gills.  Decaying debris in the aquarium can alter the environment and is the usual cause for gill rot.

The sad news is that once you notice symptoms of gill rot it’s often too late to save the eel.   There is no cure for gill rot.

White Spot is a common parasite that appear like grains of salt or sugar on the fish’s body.  Symptoms include difficulty breathing, disoriented swimming, and protruding eyes.  It is important to treat the affected fish before the parasite multiplies.

Treatments include anti-parasitic medicines and malachite dye.  Medication can only be effective when used before the parasite has multiplied.

All medicine you use should be for anaerobes so that it does not kill the good bacteria in your tank. Malachite dye is green and can fight White Spot, but not all breeds of eels can handle the treatment.

If your eel starts to grow tumors on the jaw it is possible it has Cauliflower Disease/Lymphocystis.  This is a long lasting disease but can cure itself in time.

If you maintain the preferred pH level and clean the tank on a regular basis, you can avoid unhealthy eels.  Illness prevention will always be worth any effort you put forth.

Conclusion

Freshwater eels are easy to care for depending on the species.  Always look into what they need for equipment and care before purchasing one.  If you can follow the maintenance and feeding schedule, you will not have an issue.

Eels are great for those looking to advance beyond beginner aquariums.  Their looks add contrast and grow your ability as an aquarium hobbyist.  Fish keeping is relaxing for both young and old to partake in and enjoy together.

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