Black Ghost Knifefish – Habitat, Care, Feeding, Tank Size, Breeding

The black ghost knifefish is one of the most unique fish you can keep in your aquarium. Just as the name suggests, this fish is entirely black. Except for a white stripe running from its nose to the back and two white rings on the tail.

Scientifically known as Apteronotus Albifrons, the black ghost knifefish is an elegant and mesmerizing fish, unlike most others.

It doesn’t have fins nor scales, and its tail assumes the shape of a rod. What’s more, this fish has a weak electrical organ at its caudal peduncles for locating food.

If you’re looking to introduce this unique fish to your aquarium, it’s best to first understand everything there is to it. Or everything important at the very least.

With this in mind, here’s a comprehensive guide to rearing black ghost knifefish:

Black Ghost Knifefish Natural Habitat

The black ghost knifefish originates from South America. In fact, its name- ghost knifefish- originated from folklore tales of Amazon Jungle tribes who believe that dead souls inhibit these fishes. Interesting, eh?

The black ghost knifefish has mostly lived in the Amazon River and throughout its tributaries. Yes, its natural habitat stretches from Paraguay and Venezuela down to Peru’s freshwater basins.

It’s important to note that these waters have lots of vegetation with numerous crannies and nooks to hide. Also, they are quite murky with moderate water currents and low lighting.

Equally important, the areas where black ghost knifefish natively reside have a tropical climate as well as sandy bottom creeks.

Black Ghost Knifefish Aquarium Requirements

Ghost knifefish are normally a shy bunch and naturally nocturnal. Meaning that they thrive in a tank featuring many hiding places since they’ll spend most of their daylight hours unexposed.

As such, plants and smooth rocks in addition to subdued or dark lighting are a must-have in your aquarium.

Remember, black ghost knifefish are scale-less, and so you should put a fine substrate like gravel mix or sand in your tank to prevent injuries. And when it comes to tank size, a minimum of 150 gallons will be fine. What else?

A high-quality filter and a UV sterilizer will come in handy when it comes to keeping the tank clean and free of diseases.

Take note that black ghost knifefish are extremely sensitive to medications. So you want to keep them as healthy as possible. Some aquarists go as far as installing a clear tube for the fish to hide in.

This essentially kills two birds with one stone. The fish can remain hidden and the owners still get to see them.

And now comes the best part. Once black ghost knifefish acclimate to their new home, they’ll leave their hiding places during feed time. You can even teach them to feed from your hand.

Not only that. Ghost knifefish can become so trusting and tame that you can hand-hold them. How cool is that?

Black Ghost Knifefish Water Conditions

When it comes to black ghost knifefish and water conditions, the parameter windows are quite flexible. Meaning that these fish tolerate a range of water conditions.

If anything, they have an electric organ for food searching because their habitat (natural) is anything but clean.

However, these fish are extremely sensitive to shifts in water parameters. Water stability is, thus, key with the ghost knife fish. Also, avoid suboptimal water conditions as these fish can’t survive in average quality water like other more hardy species.

Considering how important general water quality and parameters are important to ghost knife, it’s advisable to invest in an excellent water test kit.

Make sure that the readings and levels are as accurate as possible. This will go a long way in helping you make vital decisions on how to treat your tank’s water.

On the whole, keep the following water condition ranges in mind:

  • Water temperature: 73 °F to 80 °F
  • pH levels: 6.5 to 8
  • Water Hardness: 0- 10 KH

Black Ghost Knifefish Diet and Feeding

The best diet for ghost knifefish is almost identical to what they feed on in their natural habitat. Unlike many other species, these fish tend to resist transitioning over to pellet or flake foods. It’s, thus, ideal to offer them what they love-natural diet and protein-rich foods.

As you may know, the black ghost knifefish is an omnivorous species. So any of the go-to frozen or live food will work. Though feeding them a variety comes highly recommended. Most owners use prawns, brine shrimp, bloodworms, and tubifex.

Considering that ghost knifefish are nocturnal, you’ll need to figure out their sleep cycle. It’s best to feed them once a day and do it in the night or evenings (depending on your schedule).

And be consistent with the timing to ensure your fish recognize you and become most active during feeding time. Not only that.

Make sure you also don’t overfeed your ghost knifefish. This is a mistake many owners make early on their ownership journey. Remember, fat fish are sick fish.

Yes, overfeeding your ghost knifefish negatively impacts their health in addition to increasing the amount of waste produced into the aquarium, compromising its water quality.

If your fish can’t consume all the food you provide in a few minutes, reduce the quantity.

Black Ghost Knifefish Tank Mates

Black ghost knifefish are relatively active fish that like to stay isolated and do their own thing. They spend most of their active time minding their own business, swimming across hiding spots near the substrate searching for food. Anything else is a stress they want to avoid.

Nevertheless, ghost knifefish can be aggressive. This mostly occurs when they are around other black ghost knifefish. But that doesn’t mean you shouldn’t keep more than one ghost knifefish.

As long as each of your fish has enough space to establish and develop its territory, ghost knifefish won’t be aggressive towards each other. If you cram two or more together, they’ll quickly get grumpy. How? Ghost knifefish have bad eyesight and so they’ll end up bumping into each other when searching for food.

Aquarists recommend keeping only two ghost knife per tank to keep the potential for aggression at a minimum. How about other tank mates?

Any peaceful freshwater fish will exist peacefully with your ghost knifefish as long as they are not too small (less than 6 inches in size) to get eaten.

Here are some of the most popular black ghost knifefish tank mates:

  • Silver Dollar fish
  • Electric Blue Acara
  • Oscar fish (this pairing needs plenty of space)
  • Cory Catfish
  • Rope fish
  • Bichir

For the perfect fish community, pair your adult ghost knifefish with Angelfish, catfish, large peaceful Cichlids, Corydoras, and Discus.

Corydoras are excellent companions as they help keep your tank clean. If you’re housing young ghost knifefish, pair them with smaller-sized fish like Guppies, Tetras, Rasboras, and Barbs.

Gastropods (such as snails and shrimp) and small crustaceans are the perfect food for your black ghost knifefish. As such, don’t pair these two species together.

Black Ghost Knifefish Breeding

Aquarists know very little about breeding the black ghost knifefish. Because of the lack of information on the process, people try many conflicting breeding methods. Which makes it quite difficult to know what works and what doesn’t.

Still, in places like Indonesia, aquarists breed tank inhabitants in ponds. The main reason for this is that it’s not suitable to breed this species without dedicated aquariums, though it’s possible. Even so, successful black ghost knifefish breeding requires the following:

  • A mated pair of adult ghost knifefish. The pair must be ready to mate and compatible. Experts consider this stage the most difficult part.
  • An extra-large tank positioned in a darkened location away from excessive movement and noise
  • Pebbles, plants, and large pebbles to stop the parents from accessing the eggs after they get laid. This is vital since adult ghost knifefish tend to consume their eggs.
  • A water temperature of 27 degrees, which is the optimum breeding temperature
  • Consistent water changes (Between 25 and 50%, recommended at least every two days). This indicates ‘wet season’ and encourages your fish to breed.

All in all, water consistency is vital when breeding ghost knifefish. Also, these fish are likely to breed successfully when they’re in a non-threatening environment, free of stress.

If the mother doesn’t feel safe in your tank, she won’t lay any eggs. And in as much as ponds make excellent locations for breeding, they make it quite difficult to collect the eggs or control the young.

You see, once the female lays the eggs, you should immediately remove it from the aquarium or pond. Black ghost knifefish don’t attach to their eggs or young ones and will readily consume them if given the chance.


Watching black ghost knifefish swim in your aquarium is one hobby that never gets old. As such, investing these fish can be very rewarding if you’re willing to do everything necessary to keep them healthy. So be as honest with yourself as possible.

The worst thing you can do is invest in a species that you can’t handle. If you think ghost knife fish are the most ideal for you, prepare to dedicate some effort and time to the adventure of keeping them. Trust, you won’t regret it.

Knifefish   Updated: June 10, 2020
avatar Hey, I'm Fabian, chief editor at Aquarium Nexus. I really enjoy the aquarium hobby and love sharing my experience with others. If you have any questions feel free to contact me or leave a comment below.

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