Care Guide For Black Ghost Knifefish – 18-Inch Electrical Oddball Fish

Care Guide for Black Ghost Knifefish – 18-Inch Electrical Oddball Fish

This care guide is often requested by people because knifefish are unusual looking curiosities. They have an undulating fin which allows them to swim forward and backward. There are many types of knifefish available, but the black ghost knife (BGK), is the most common and sought-after. Unlike your average betta fish though, it is a considerably larger pet that requires a ton of room and may live for over a decade. Let’s discuss what it takes for this oddball fish to be happy and healthy long-term before you commit.


What is a Black Ghost Knifefish, you ask?

Apteronotus albifrons is a South American nocturnal fish that has weak eyesight and instead uses electrical signals to navigate its surroundings. The common name “knifefish” comes from the fact that it has no dorsal or caudal fin, giving it a blade-like appearance. An extended anal fin runs along its bottom edge and ripples backwards like a wave. This allows the knifefish to maneuver in bidirectional fashion between tight spaces.

Most black ghost knifefish are captive-bred nowadays and may cost $15-20 or more, depending on the size of the individual. Sometimes, young fish are sold in overcrowded tanks. They may get into problems with other fish. So make sure to buy a healthy one with both the white spots and a tail. You can expect this fish to live for as long as a pet dog. Ask the employee at the store to feed your knifefish before you bring it home.

A healthy knifefish should be able to carry a lot of weight and have an active tail.

How big does a black ghost knife get? They can get pretty large if you are feeding them enough, so don’t be surprised if your baby knifefish matures into a 14- to 18-inch (35-45 cm) beast.

How fast does black ghost knife fish grow in their care? After the first year, they reach a height of 8 inches (20cm) and then slow down to 2 inches (5cm) per year.

Are black ghost knifefish tough? Some people think they are “sensitive” fish that can’t live long. However, we have not had that experience. We have found that they do well when we feed them properly, don’t pick on them, and maintain good water quality. This is just like any other fish. Fish can usually handle one stress factor but health problems are more likely if there are multiple stress factors.

Will a ghost knifefish shock you? This is because it is weakly electric, unlike a stronger electric fish like an electric eel. An electric organ in a knifefish creates a weak electrical field. Then it has various sensing organs that can detect any distortions to this field. This is similar to a radar. This detection system helps the knifefish to navigate its surroundings, locate prey, and communicate with potential mates or intruders.

How to Set Up an Aquarium for a Black Ghost Knife

Let’s discuss tank size. A 55-gallon aquarium might be okay for the first year, but it is too small for the long term. A 75-gallon fish aquarium is the next upgrade and may last for several more years. Ultimately, we recommend getting a 120- or 180-gallon aquarium for an adult black knife fish. They can tolerate a pH between 6.8-7.8, temperature between 75 and 28degC (24-28degC), as well as GH levels of at least 5deg (90ppm). Create a heavily decorated setup with low lighting and lots of nooks and crannies – such as clear PVC pipes, rock caves, pleco caves, large driftwood, and aquarium plants. You can increase the size and comfort of your shelters for them as they get larger.

Plecos may quarrel with your knife fish over the best hides, so provide more caves if needed.

Is the black ghost knifefish aggressive? In the right conditions, they can live in a community aquarium with other similar-sized, peaceful fish. It is not a good idea for tank mates to bully or outcompete them for food. Neon tetras are a favorite food of adult knifefish, as well as any small fish, so keep any nano fish away from your tank.

What kind of fish can live with a ghost knife? Some hobbyists keep adult BGKs alongside peaceful catfish, geophagus cichlids and other friendly tank mates.

Can 2 black ghost knifefish live together? We don’t recommend it since problems tend to arise. Knifefish can be territorial and won’t share their space with other electric fish like baby whale fish, elephant nose fish and other knifefish. Obviously, anything is doable if you have a large enough aquarium, but most people tend to keep ghost knifefish in undersized tanks.

What do Black Ghost Knife Fish Eat?

They are easy to care for and can eat a predominantly carnivorous diet. Despite being a bottom dweller, they willingly go after both floating and sinking fish foods. Our worms are fond of brine shrimps, bloodworms as well as a wide variety of other foods, including worms, bloodworms or pellets. They will predate on small invertebrates and fish once they reach adulthood, as we have already mentioned.

Black ghost knives may be shy at first, and will spend the day hiding in their favorite spot until they are ready to eat. Many people have taught their black ghost knives to eat from their hands and the water surface using floating food.

Black ghost knife can be used to teach Black to swim up to the surface to eat from your hand.

Are black ghost knife fish allowed to eat flakes? It is possible for them to be outcompeted by other species of fish when it comes down to food. We prefer to feed our fish pellets, freeze-dried, or frozen food to maintain a healthy weight.

This showpiece fish is such a fun and cool-looking species to own. The black ghost knifefish is a great pet if you’ve done your research thoroughly and are ready to buy a large tank. We do not ship fish. However, you can check out our recommended online retailers to see what stock they have.