Spotfinned spiny eel Care Guide: Diet, Tank Mates, Diseases, Breeding & More

Updated: December 17, 2022

The Spotfinned spiny eel is a beautiful and unique freshwater fish that is perfect for the intermediate fish keeper.

This species is relatively easy to care for, but does require a bit more attention than some of the other fish on this list.

But if you’re up for the challenge, the Spotfinned spiny eel is a great addition to any freshwater tank.

In this guide, you’ll learn everything you need to know about Spotfinned spiny eel care. Tank size, diet, tank mates, and more. It’s all here!

Species overview

The Spotfinned Spiny Eel (Mastacembelus armatus) is a freshwater fish that is native to tropical Africa. It is found in rivers and lakes throughout the Congo Basin.

This eel is nocturnal and prefers to live in areas with plenty of hiding spots. This could be among rocks, plants, or wood.

The main diet of the Spotfinned Spiny Eel is small invertebrates, although they have been known to eat the occasional fish.

This eel gets its name from the spots that are on its fins. These spots are black and help the eel camouflage itself among the rocks and plants in its natural habitat.

The Spotfinned Spiny Eel is a popular choice for aquariums because of its unique appearance. It is important to note that this eel can grow to be quite large, so it is important to provide it with plenty of space to swim.


Spotfinned spiny eel

This is a long fish that can grow up to 3 feet in length! They have a slender body that is covered in small scales. The body tapers down to a point at the end.

The dorsal fin is located about halfway back on the body and is tall and thin. The anal fin is located on the underside of the body and is also tall and thin. Both of these fins are spinous.

The pectoral and ventral fins are located on the sides of the body. The caudal fin is forked and located at the end of the body.

The head of the fish is narrow with a small mouth. The eyes are small and located on the top of the head.

The body is pale with dark spots. The spots are more pronounced on the dorsal and caudal fins.


The average lifespan of a spiny eel is between 3 and 5 years. However, there have been reports of these fish living up to 10 years in captivity.

As with most fish, the lifespan of a spiny eel is greatly impacted by the quality of care it receives. Things like water quality, diet, and stress can all shorten their lifespan.


The average Spotfinned spiny eel size is between 8 and 10 inches in length when fully grown. However, they can grow to be up to 12 inches long in some cases. These eels are slender, but they can get pretty big!


Tank Size

A 75 gallon or larger aquarium is recommended for a single adult fish, and 125 gallons or more for a pair.

Spiny eels are relatively inactive fish and don’t require a lot of swimming space. However, they do need a hiding place and plenty of places to hide. A densely planted aquarium with hiding places amongst the plants is ideal.

Caves, driftwood, and rocks can all provide good hiding places for spiny eels. Be sure to give them plenty of options so they can feel secure in their new home.

Water Parameters

The water parameters for a Spotfinned spiny eel are relatively straightforward. These fish come from slow-moving, warm rivers and streams in Southeast Asia.

To recreate this environment in your aquarium, you’ll need to maintain the following water parameters:

  • Water temperature: 75 to 82 degrees Fahrenheit
  • pH levels: 6.5 to 7.5
  • Water hardness: 4 to 10 dGH
  • Alkalinity Levels: 2-8 dKH

What To Put In Their Tank

Spiny eels are a little different when it comes to setting up their home. They’re not too picky about the substrate and can live in both fresh and salt water.

We recommend using a sand substrate since it’s softer on their bodies (they like to burrow a lot). You can also use gravel, but avoid anything too sharp or jagged.

The inside of their tank should be pretty bare. They don’t need any plants or decorations. In fact, too many things can stress them out.

The only thing we recommend putting in their tank is a hiding place. This can be something as simple as a cave or a piece of driftwood.

Since they’re nocturnal animals, they’ll spend most of the day hiding away. Having a hiding place will help them feel more comfortable and reduce stress levels.

Common Diseases

These fish are actually quite hardy and don’t usually get sick. However, there are a few things you need to watch out for to make sure your fish stays healthy.

The most common disease you’ll see in these fish is ich. This is a parasite that can cause a lot of trouble if it’s not dealt with quickly.

The most obvious symptom of ich is the presence of white spots on the body of your fish. If you see this, it’s important to act fast and begin treatment immediately.

Other than ich, the other thing you need to watch out for is infection. This can happen if your fish gets a cut or scrape.

The best way to prevent this is to make sure the tank is well-suited for these fish. They need a soft substrate and plenty of hiding places to feel secure. If the tank is too small or doesn’t have the right type of substrate, your fish may become stressed and more susceptible to illness.

Behavior & Temperament

The Spotfinned spiny eel is a very peaceful creature that spends the majority of its time hiding in caves or other dark places in the tank. They are nocturnal animals, so they are most active at night.

During the day, they like to stay hidden away from the light. When they first wake up, they may be a little grumpy and not want to be bothered. But, once they have had time to adjust, they will be their normal, happy selves.

Spotfinned spiny eels are not aggressive and will not bother other fish in the tank. In fact, they are quite shy and will do their best to avoid confrontation. The only time they may become aggressive is if they feel threatened or are not getting enough food.

Tank Mates

Spotfinned spiny eel tank mates are limited to species that can handle brackish water conditions.

This is because the eel is native to brackish estuaries and mangrove swamps. These environments have a mix of fresh and saltwater.

As a result, the eel isn’t comfortable in either extreme. They do best in an environment that’s somewhere in the middle.

The good news is that there are plenty of brackish water fish to choose from. Here are some compatible spotfinned spiny eel tank mates:


Spotfinned spiny eels are difficult to breed in captivity. It’s not impossible, but it does require a lot of care and attention. These fish are very sensitive to changes in their environment. Even the slightest change can impact their health and wellbeing.

The first step is to set up a breeding tank. It should be at least 30 gallons in size. Then, add some hiding places. These fish like to have a lot of places to hide. Driftwood, caves, and plants will all work.

Next, you need to adjust the water parameters. The pH should be between 6.7 and 7.2. The water hardness should be between 5 and 10 dH. The temperature should be between 75 and 82 degrees Fahrenheit.

Once the tank is set up, it’s time to add the fish. You’ll need one male and two females. The male is usually the larger of the two. He’ll also have longer fins.

Once the fish are in the tank, you need to feed them live food. Worms, brine shrimp, and bloodworms are all good options.

The next step is to wait. These fish take their time when it comes to spawning. It can take weeks or even months for everything to come together.

When the female is ready to lay her eggs, she’ll do it in a hidden area of the tank. The male will then fertilize them. After that, he’ll stay with the eggs and protect them.

It takes about two weeks for the eggs to hatch. When they do, the fry will be very small. They’ll need to be fed live food. Baby brine shrimp are a good option.

As they grow, you can start to introduce other foods. pellets and flakes will work. Just make sure that the food is small enough for them to eat.


Spotfinned spiny eel care can seem daunting at first, but it’s not as scary as it seems once you learn about them.

Sure, there are some different things you’ll have to be mindful of, but we think it’s worth it.

These fish make great additions to community tanks but also do very well when kept with a few of their own kind. This gives you some options with how you want to keep them once you understand how to keep them healthy and ensure that they thrive.

Overall, we’re big fans of the Spotfinned spiny eel and highly recommend them to tank owners who want to mix things up a little bit!