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Black Ghost KnifefishBlack Ghost Knife Fish

Family: Apteronotidae (Ghost Knife Fishes)

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Black Ghost KnifefishApteronotus albifronsPhoto © Animal-World: Courtesy Ken Childs

    The popular Black Ghost Knifefish is readily distinguished from other knife fish by the white and black banded area just in front of tail fin!

     The Black Ghost Knifefish received its unusual name because of a rumor that some tribes in the Amazon jungle believe that the souls of the dead inhabit this fish. No one can substantiate this information and it may just be a story created by the people collecting the fish, but it's a good story.

     For good reason, the Black Ghost Knifefish is the most well known species of knifefish in the aquarium industry. One reason for this is that they have been imported for decades. Other reasons include being unusual, interesting and amazingly beautiful. Until a few years ago, all offered for sale were wild caught and had been imported from South America, mainly from Brazil. The good news is that they are now being bred in Indonesia by the thousands, so much of the pressure has been taken off the wild populations. Odds are that if you see an individual of 5 inches or more offered of sale, it was collected in the wild. Specimens smaller than 5 inches were most likely produced in and imported from Indonesia.

For more Information on keeping freshwater fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:      The Black Ghost Knifefish was described by Linnaeus in 1766. Black Ghosts are found in South America throughout much of the Amazon River and its tributaries. It is nocturnal and preys on insect larvae.

Status:      The species is not listed on the IUCN Red List.

Description:      The black body of the Black Ghost Knifefish is flat and elongated. It has a continuous fin along the underside formed by a joining of the caudal and anal fin and moves with an undulating motion. Although they appear clumsy, they have a built in ‘radar' system that uses low voltage electricity to help them navigate. This and their undulating lower fin allow them to gracefully move forwards and backwards through the aquarium.

Size - Weight:     The maximum size for this fish is around 20 inches (50 cm).

Care and feeding:      The Black Ghost Knifefish are carnivores. In the wild they are nocturnal, when the sun sets and throughout the night they feed on insect larvae. In the aquarium this is a fish hat prefers fresh or fresh frozen foods such as bloodworms, brine shrimp or blackworms.
     A full sized Black Ghost Knifefish is a big animal which requires a big home. You will need to eventually provide a tank containing 100 gallons or more if you plan on keeping one of these beauties into adulthood. Providing many hiding places with plants, smooth rocks or aquarium safe wood in a necessity. They are nocturnal and will spend most of the daylight hours hiding in a safe and secure location. Once acclimated to their new home, they should come out of hiding at feeding time. Some have even been taught to feed from their keeper's hand.

Water Region: Top, Middle, Bottom:     This species of knifefish spends most of its time near the bottom.

Acceptable Water Conditions:      Temp: 73 - 82 ° F (23 - 28 ° C)
     Hardness: 5 - 19 dGH
     pH 6.0 to 8.0

Social Behaviors:      Black Ghosts can become aggressive with members of their own species and members of other, similar species. Other than that, they are usually quite timid. They do have a large mouth so small fish or invertebrates kept in the same tank may eventually become a meal for a hungry Black Ghost.

Sexual Differences:      Sexual differences are unknown.

Breeding/Reproduction:      This species is being bred commercially in Indonesia but the method used is unknown. There are hobbyists that claim to have successfully bred the Black Ghost Knifefish in an aquarium but they seem reluctant to share the details. There is some information on this subject, scattered reports, but there is nothing yet documented from reputable sources so it will not be reproduced here. One thing for certain is that if you want to give it a try, you'll need a big aquarium, probably containing 100 gallons or more.

Buy Black Ghost Knifefish From LiveAquaria.com

Availability:     Now that they are being bred in captivity, the Black Ghost Knifefish are available all year long.
Large specimens may command a high price, mainly due to the higher costs of shipping them. Smaller specimens are quite affordable.

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Latest Comments
Kyle, Plecos and bottom feeders are included in that... they are bottom feeders and they count as fish. Yeah, it is over crowded with a freaking 10" pleco. J 2010-02-01
Kyle, your 44 is overcrowded. The 1" per gallon rule doesn't hold true when dealing with large fish - it simply doesn't account for the amount of waste produced. I agree with Koop. Rehome some of your fish. Z. 2010-01-19
I have a 29 gallon tank with quite an assortment of fish ranging from bettas, sharks, dragon fish, and one ghost knife I call my queen. She is beautiful and seems quite content. although she stays hidden during the day she comes out at night and eats from our hands. She is definitely my favorite! Tommie 2009-12-29
My 44 gallon tank is not overcrowded. Firstly most knifefishes never grow 20 inches in aquariums, that twenty inches is based on a wild caught specimen out of the spacious amazon river. Secondly, have you heard of the inch per gallon rule. Every inch of fish needs a gallon of water. Tiger barbs and flying foxes grow three inches long; 6 total, times 3 inches equals 18 inches and a required 18 gallons of water. The 18 inches of the barbs and flying foxes and the 12 inches of firemouths and the 5" knifefish puts me not only under the limit according to the inch per gallon rule; but allows the knifefish to grow to a length of 14" long. Thirdly, knifefish are one of the slowest growing species of freshwater fish in the world. It will take years for my knifefish to even reach 14" in length. By the time he reaches 14", almost everything else in my tank will be dead. That's how long it takes knifefish to grow. I bought mine over two years ago when he was just under three inches long. That is an inch per year growth rate. And when he does get long enough, I have a 200 gallon tank with oscars he can move into. I am just growing him out in my more peaceful tank until he is big enough to live with some oscars with out getting eaten. Lastly, bottom feeders like plecos don't count towards the space required for the tank. Check your facts before criticizing someone who has 25 years of experience with fish. Kyle 2009-12-27
I have a 350 gallon tank with a small amount of fish. I have 3 dragon gobies that seem very timid and 3 ghost fish that only come out at night. I'm very fond of this type of fish but am having trouble finding out other types of fish to put in it. My oscars and parrots oddly get along great. I need some suggestions on other fish that will get along to put in my tank. mckenna 2009-12-02
Some of the coolest comments:
I got two black ghost knifes a year ago and they get along fine. I've been feeding them frozen bloodworms and they've started eating out of my hand. They seem to have gotten used to the light, now it looks like they couldn't care less if the lights are on or off, but when I turn off the lights, they immediately rush out of their caves and swim vertically along the top of the water, looking for food. Most awesome fish ever! Josh 2009-09-02

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