Raising regular old freshwater aquarium fish is fun, but it can get boring after a while. From snails to frogs, there are plenty of other creatures you might want to include in your freshwater tank.
But have you given freshwater aquarium eels a try? These slippery creatures might not be for everyone, but if you have some level of familiarity with raising fish in an aquarium, you can raise these creatures with no problems.
Eels aren’t suitable pets for everybody, but for the right person, they can offer an enjoyable alternative to regular fish. Here is an ultimate guide to teach you everything you need to know about these slimy delights!
While there are several different types of freshwater aquarium eels that you can choose from, true eels identify within the order of Anguilliformes. With other bony vertebrates, eels occupy this category. Common varieties of eels include the Moray eel, the American eel, Spaghetti eel, and more.
Unlike the rest of the eels in this order, however, freshwater eels are those that first spawned in the ocean before moving to freshwater. Freshwater eels will spend a significant segment of their lives in these freshwaters, surviving in completely fresh or somewhat brackish environments.
At some point, most eels will need to relocate. Since eels are technically marine creatures, they need some salinity in order to survive. As a result, the term “freshwater aquarium eel” is somewhat of a misnomer – there is no such thing as a truly freshwater-adapted eel.
Sadly, most people do not know this – and purchase freshwater aquarium else at the aquarium store thinking nothing of it. The eels are marketed as suitable for freshwater, and they die shortly after being placed into a freshwater tank. Since the eels can’t fulfill their life cycles naturally, the way they would in the wild, they cannot survive.
Unlike other species that are mistakenly labeled as freshwater species, eels cannot ever learn to adapt.
As a result, when you are looking for freshwater aquarium eels, you may want to look for a fish that is not a true el but instead, an eel look-alike that can survive in freshwater. True eels must return to saltwater, no matter what your fish store might claim.
Therefore, it’s better to choose one of these looks-alikes for best results. Here are some of the most popular varieties, as well as tips for keeping them healthy.
1 Kuhli Loach
The Kuhli loach is one of the most popular eel-like fish species. It is a curious creature that does well in a small- to medium-sized tank. It is highly curious and enjoys being around other fish, too.
These fish don’t grow quickly, only reaching a maximum size of 4 inches or so. That being said, you can’t scrape by with a tiny tank for these little fellas! You need to have a large tank – around 125 gallons when the fish are mature.
Why? Kuhli loaches are small fish, but they like to hang out at schools. You need to keep them with members of their own kind, ideally at least in groups of three or larger. If you don’t keep your kuhli loaches in a school, they will become incredibly shy and you will rarely see them in your tank. This can cause some serious issues with isolation.
Also known as coolies, kuhli loaches look and act a lot like regular eels. They are primarily nocturnal, scavenging for food mostly after sunset. They like to burrow in the and, too, and can even squeeze through super-tiny holes. As curious little critters, they often end up in your filter outlet! Therefore, make sure it is well-secured.
2 Electric Eel
The electric eel is a super difficult fish to raise – unless you’re a specialist, that is. You need to have a ton of experience raising fish in order to raise an electric eel, which is technically part of the knifefish family.
These fish can’t be kept in regularly-sized tanks, either – they need to be kept in tanks of at least 540 gallons for adults!
Plus, there’s some risk involved in raising electric eels. These creatures can produce electricity at up to 600 volts and 1 ampere. Repeated shocks can stop your heart -as a result, you will need special gear in order to maintain your tank. Even regular water changes can result in a shock.
You also can’t keep an electric eel with other tankmates. They’re large fish, growing up to 95” long, and since they are so deadly, it really doesn’t make sense to keep them unless you are somehow involved in specialty collecting.
3 Asian Swamp Eel
Also known as the Rice eel, this species is admittedly not for the faint of heart. It can reach nearly four feet in size, and since it is so large and aggressive, it’s only for expert fishkeepers.
This fish prefers tanks with temperatures of around 78 to 82 degrees Fahrenheit. It needs to be kept in a tank that is no smaller than 180 gallons. You need to make sure the fish has plenty of space to stretch out, and you also need to keep the water quality in check. These eels are particularly prone to fungal infections and can also become extremely aggressive if they feel overcrowded.
What’s interesting about Asian swamp eels is that they are even more aggressive as young juveniles. It is not uncommon for them to bite or even kill fish who are larger than them. The fish has super strong jaws that can easily kill anything they come into contact with.
Once your rice eel matures, you won’t have to worry about its violent behavior quite as often – it will hang out close to the surface of the water and will be so large and lethargic that it won’t be interested in terrorizing other tankmates any more.
That being said, most expert fishkeepers choose to keep this eel alone so that it doesn’t attack other fish. You can also keep it with super large fish, ideally those that are at least ten inches long.
Asian swamp eels are not like other eel-like fish in that they are not terribly shy. However, it’s best to still include some hiding spots, as the Asian swamp eel likes to hang out in dark caves from time to time. These fish can live for eight to twelve years when cared for properly.
4 Tire Track Eel
Tire track eels are interesting creatures, with each individual of the species possessing a character that is uniquely it’s own. These fish can be a bit shy at first but will gradually grow to become quite comfortable inside your tank.
Tire track eels prefer tanks with temperatures hovering around 73 to 82 degrees Fahrenheit. They should not be housed in tanks any smaller than 125 gallons. While you can get away with a smaller tank in many cases for young fish, these fish grow quickly and will rapidly outgrow a 35-gallon tank.
Tire track eels need plenty of space to themselves since they are relatively shy, they prefer to hide among the substrate. As a result, the substrate of choice should be soft and nonabrasive. Sand is the perfect option for you to consider. In addition, you will want to keep plenty of hiding spots and decorations, like PVC pipe, around.
Don’t worry – adding more hiding spots won’t encourage your tire track eel to hide necessarily. After a period of time, your fish will grow more comfortable with the environment and will come out to play more often. In fact, you may even notice that they become too comfortable, stealing from right from the mouths of their fellow tank mates!
These fish become aggressive very quickly and will eat anything that is small enough to fit inside their mouths. They should not be kept with tiny species of fish but instead housed with fish that are either larger or the same size. If you keep two of the same kind, make sure you have a larger aquarium than what we originally recommended – tire track eels can be territorial among members of their own kind.
These eels do okay in freshwater but prefer a bit of salinity in the tank. They are suited to a somewhat brackish environment and being in such an environment will boost their health. It can help prevent parasites and improve their immune systems, too.
Many people steer clear of raising tire track eels because they cannot be fed flake food. Instead, you need to feed them options like black worms, mysis, krill, nightcrawlers, and other live foods. Keep the water flowing at all times, too – this will make them feel right at home.
5 Half-banded Spiny Eel
The half-banded spiny eel is one of the smallest freshwater eels you can raise, making it the perfect candidate for aquarium hobbyists with smaller tanks.
This fish needs to be kept in a tank that is about 10 gallons as a juvenile, but as it grows, you may need to upgrade to a larger tank. Usually, though, that won’t be any larger than 55 gallons or so.
This creature is also prized for its temperament. A friendly eel, it loves hanging out with the other occupants of your tank. It likes to burrow into the substrate, fine sand is the best choice here.
The half-banded spiny eel is generally active during the daylight hours. As a result, you will need to provide plenty of hiding spots to shield it from the light and give it places to hide. Options include bogwood, castles, and rocks.
When you are selecting expansion for your half-banded spiny eel, choose those that are longer than two inches. This way, you won’t have to worry about them accidentally becoming a snack for your half-banded spiny eel! Instead, you should feed your half-banded spiny eel foods such as small crustaceans, ghost shrimp, and live bloodworms.
When cared for properly, this fish can live for more than ten years!
6 Zig-Zag Eel
The zig-zag eel grows up to 40” long!
These fish are often mistaken for tire track eels, as they have similar coloration. You can tell the two eels apart by the patterns of lines. The lines on a zig-zag eel has lines that are similar to each other, but a tire track eel will have a more random design on its back.
These designs fill out and develop more over time – it might be difficult to tell the two species of eels apart until they reach maturity.
And reach maturity they will – these fish can live up to eighteen years as long as you care for them properly!
Although they have the potential to grow quite large, most zig zag eels remain smaller in captivity – usually remaining around two feet or so. These fish grow slowly, only putting on about an inch per month when there is plenty of food.
These eels love hanging out in the substrate, hiding and looking for food. As a result, a soft substrate is best- ideally sand or fine gravel. At night, these fish will come out of the gravel. They are carnivores and will enjoy trying to fit anything they can into their mouths – which in most tanks, includes the rest of your fish!
Therefore, you will want to only include tank mates who are not large enough to get themselves considered prey. This eel has a reputation as being somewhat feisty and aggressive, so is not a good match for other tank mates that aren’t a comparable size. They will go after smaller fish when given the chance, but usually prefer to eat foods like live shrimp, frozen bloodworms, and tubifex.
7 Fire Eel
The fire eel is one of the largest of all the spiny eels, easily reaching more than three feet in the wild. Luckily, you don’t have to worry about this species growing overly large in your tank – it usually will have limited growth, only reaching about 30 inches or so.
Nevertheless, that’s still a massive fish that we’re talking about! Therefore, you should make sure you don’t invest in a tank that is any smaller than 180 gallons for adult fish. Fire eels are more or less peaceful, typically ignoring fish that they don’t consider food.
That being said, you need to avoid keeping two fire eels together in the same aquarium. They will easily become aggressive towards each other, fighting for territory. As a bottom-dwelling fish, the fire eel will occasionally spar with other bottom-dwellers too. They also compete for space.
Otherwise, you can keep your fire eel with just about any other type of fish in your tank. These fish like to burrow in the gravel and therefore need a substrate of at least 2.5” deep. Since they burrow, it is not uncommon for them to pull up plants. You may want to stick to floating plants, which will not only survive better in the bank but will also help to dim the lighting.
As you might expect, these bottom dwellers prefer an aquarium that is darker than average. They also like plenty of hiding spots, like driftwood, rocks, and caves. They are hardy fish that present few challenges to fishkeepers.
In fact, these fish are so peaceful and intelligent that they can be hand-fed! Over time, your fire eel may begin to recognize your appearance and the half seeding process will become quite enjoyable for you. You can feed these fish all kinds of food, from frozen bloodworm to krill and even ghost shrimp. As mature fish, they can eat live nightcrawlers, too.
As omnivores, fire eels are not a picky eater -but they do prefer live prey to vegetables. They are nocturnal creatures and feeders, so you may not see them poke their heads out for food at any other time.
8 Peacock Eel
The peacock eel is an excellent choice for beginners, but it can be tough to find.
However, they’re all the same. These smaller eels are more manageable than some of the other common freshwater eels. They usually only reach about a foot long, and can, therefore, be raised in tanks that are around 55 gallons.
As shy species, it can take your peacock eels some time to warm up to you. They will spend a great deal of their time hiding in the substrate – as a result, you will want to turn to nonabrasive, fine substrates of gravel of sand, layering either about two inches deep.
The peacock eel is a peaceful creature that is ideal for group tanks, which is part of the reason why it is such a perfect candidate for beginners. It will do well with other smaller, nonaggressive fish. Although it might try to nibble on super small fish like neon tetras, you usually won’t need to worry about it going after nonaggressive cichlids, ottos, or rainbowfish.
In addition, you can keep multiple peacock eels together. These fish aren’t known to become territorial and can, therefore, be raised in groups of its own kind.
Just make sure you have plenty of vegetation – the peacock eel loves to chill out among the plants. These fish also prefer water that is slow-moving, as this resembles the natural habitat of the fish. Make sure you change out the water every week, swapping out at least 20% of the water, as the fish needs super clean conditions in order to thrive.
Otherwise, these fish are easy to care for. When provided with the proper care, they can live for 16 years or more – some live as long as 20!
9 Rubber Eel
The rubber eel has a somewhat goofy appearance and is also known as the Caecilian worm. A creature that breathes air, it is actually an amphibian without legs. However, it can survive just fine in most freshwater tanks.
As long as you provide enough surface space for this fish to breathe, you won’t have to worry about keeping it in your tank. The best size is around 55 gallons.
These amphibians are unique in that they are almost totally blind. They are scavengers when they feed, and so won’t really bother your other fish. All you need to do is provide them with some earthworms or bloodworms from time to time. You can easily keep these creatures with small fish as long as they are equally quick and nimble.
It should be noted that rubber eels have very sensitive slimy coats – therefore, you will not want to keep them in a harsh substrate. They can injure themselves easily. These amphibians also discard their skins every so often, so don’t be alarmed when you notice it floating around in your tank!
These amphibians can be difficult to find locally, as there are issues related to their export and import. However, if you happen upon one, it is definitely worth keeping!
Raising freshwater aquarium eels, or “eel-fish,” is definitely not for the faint of heart. Nor is it for the aquarium hobbyist who is under-prepared without the right equipment! You need to do your research – and your shopping – before you decide to take in one of these eel-like fish prices.
First, you need to make sure your tank is equipped with a steady lid. In addition to being large enough for your fish, you also need to make sure your tank has a secure covering to avoid the likelihood of your fish jumping out of the tank.
You also need to maintain pristine water conditions. Eels are known for their hardiness, but hey are tropical and sensitive to temperatures. You need to make sure the water is kept clean since the lack of scales makes it more likely that these creatures will suffer from parasites.
Don’t rush into adding a freshwater eel or eel-like species to your fish tank. However, once you have the right conditions, know that raising a freshwater eel is a fun hobby that can spice up your existing tank!