Animal Stories - Black Ghost Knife Fish

Animal-World Information about: Black Ghost Knife Fish

The Black Ghost Knifefish is the most well known species of knife fish in the aquarium industry!
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katelyn hampton - 2012-02-11
I have recently bought a BGK and I have been trying to feed it blood worms,brine shrimp, and mysis shrimp. I have not seen it eat anything and I am concerned that it is not eating please reply soon.

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  • Charlie Roche - 2012-02-11
    Your little guy is probably just fine. It takes them a couple of days to aclimate to new surroundings.
  • Alex Burleson - 2012-02-11
    It is not uncommon for them to not eat during the first few days that they're adjusting to their environment. Continue to feed the fish, and eventually, he should eat. Additionally, Knifefish, tend to be more nocturnal. Feed the fish, with the lights off.
  • Collecting Clownfish - 2012-02-14
    Those are SO cool! I do know that the only time I remember having success with them, was when there were not too many bottom feeders to compete, no aggressive tank mate, and larger water changes. They like their water 6.0 to 8.0 pH, but more importantly, the stability of this pH, and the cleanliness of the water quality. They are very sensitive to any water quality changes for the bad. I have read 40% to 50% every two weeks being the optimum in keeping this eventually 20' long fish alive.

    If your tank is very well established, there may be foods in the substrate he is eating. Look at his sides and see if they are thinning. Getting LIVE black worms or blood worms that wiggle may be what he needs as far as getting a feeding response. BGK can be funny in that they suddenly change their personality even IF feeding at first, so don't take it personally. You may want to check your water parameters, look and see what other fish are possibly scaring your BGK and look at his sides to see if he may be eating while you are sleeping. Otherwise, enjoy your cool fish!
  • katelyn hampton - 2012-02-14
    Thank-you for responding so quick I do feed him in the dark I have had him for a little over a week
  • Jeremy Roche - 2012-02-17
    Try some Tibifax worms. Sometimes in an overfed tank the Knife with will eat off the bottom while you sleep. If the Knife is maintaining size it is probably just shy. May just be a trial and error on that it likes to eat. Any aggressive fish in the tank with it? Water testing should be done as well to make sure that isn't putting extra stress on it.
  • Kay - 2012-03-19
    I have two and they are so Awesome! - They are extremely active. The one I had in the past never came out during the day, but these are constantly showing themselves. They love the frozen Plankton best, but do enjoy the blood worms. They are probably one of the coolest fish I have had the pleasure of caring for.
Brittany - 2012-02-10
I was thinking about getting a BGKF, but I have 4 Dojo Loachs, and 3 Bala Sharks. Does anyone know if this would be a bad idea or do you think they would be alright? I dont want anyone of them to get killed.

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  • Clarice Brough - 2012-02-16
    The Black Ghost Knife is an awesome fish. They can get aggressive with their own species, and other knifefish. But would probably be okay with the Dojo's and Bala Sharks in a large enough aquarium. Both the Black Ghost and the Bala Sharks get very big, so 100 gallons minimum to start and then you'll need a larger tank as they grow.
samiran roy,india - 2011-11-04
I have a BGK which i bought when it was about 2 inches a after a six month period it has grown to around 7 and a half inches and has consumed lots of pellet food in the process.

Chad H. - 2010-09-13
I have a 55 gallon aquarium that houses 2 Clown Loaches, 3 Tiger Barbs, 1 Pleco, 1 Khulli Loach, & 1 Blind Cave Tetra. I am fascinated by the Black Ghost Knife fish....would it be a good addition to my tank? I have 3 caves for hiding space and will add more if needed.

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  • jake - 2011-10-12
    Be careful with the tiger barbs. I have 3 in my tank (plus other fish). I put in 2 bgkf, one of which didn't have all the white on its tail, just a white tip which the tiger barbs bit whenever it was out..... sadly it died not long after. In saying that however, the other bgkf is doing extreammally well!
david - 2011-06-12
Can I keep an Apteronotus albifrons in a 55 gallon aquarium with 2x Geophagus steindachneri and 3x Metynnis argenteus?

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  • Charlie Roche - 2011-06-13
    Nope-sorry. The Knifefish needs a minimum of 100 gallon tank on his own. They can be agressive and they do get huge and if it fits in their mouth, they will attempt to eat it.
  • samiran roy,india - 2011-09-02
    If the BGK is about 2 inches, it can be kept, but you should have a future planning for the fish because they get to be 40 cm or more.
Andrew Prosser - 2011-07-26
I had two black ghost knife fish. For some reason they both died . I don't know why. If anybody has a clue why they died, Please let me know.
I bought another one last he doing pretty good.
What that kind of fish usually eat? The night I bought some guppies for them to eat.

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  • Charlie Roche - 2011-07-27
    Any symptoms - strange behaviors - anything? How long had you had them? Check out Fish Diseases and Treatment - link should be here and see if your ghost displayed anything at all unusual as described in the symptoms. Also, check to make sure your tank and living conditions are appropriate for that size fish. They need lots of room. Animal World recommends at least a 100 gallon tank.
  • samiran roy,india - 2011-09-02
    They relish on neon tetras.
jeff wilson - 2011-04-05
Is $8.94 to cheap for black ghost knife fish, and is the ph a big deal for them?

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  • JC - 2011-08-16
    Yes it's a good deal half the normal price.
  • samiran roy,india - 2011-09-02
    i got mine which is about 2 inches for 100rs, which is about 2 dollars.
Tori - 2011-08-29
My ghost knife is out all the time cruising round for food,it eats everything I put in tank. I have a community tank and feed bloodworms,pellets,flakes,turtle food. He loves to swim upside down on surface of water hoovering up food,and eats from my hand every night along with the Siamese fighter. He is a very cool fish and am surprised how active he is!!

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  • Anonymous - 2011-08-29
Marianne Tacliad - 2011-07-20
i just bought my black ghost knife about 3 weeks ago and I put him with my 7 wagtail platys, 5 zebra danios, 5 cory cats, 2 albino red-tailed shark, 1 betta and 5 black mollies including 2 of its fries. I read in some comments that they eat other fishes especially smaller ones, but mine doesn't. He's very gentle to his tankmates and he eats feed granules (with spirulina algae and shrimp enzyme) more than bloodworms (funny, considering they're carnivorous) especially if the granules sink to the bottom like rain. He comes out of his house (he usually stays inside the nipa hut-like ceramic decor) and catch the falling feeds with his mouth. The only thing he murders is the cabomba plant. My mom saw him twice with the plant in his mouth running around the tank like a torch bearer. She says it's hilarous. I wish I caught it on cam so I can upload it.

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  • Charlie Roche - 2011-07-20
    I sincerely hope you have one absolutely totally enormous tank because that is a whole lot of fish and just based on 1 inch per adult size needing a gallon. You say the Black Ghost Knife doesn't eat the other fish. The sentence is a little off. The Black Ghost Knifefish HASN'T eaten any other fish "YET" It will. The Black Ghost is going to go about 20 inches and anything he can get his mouth around, he is going to eat. You might want to re-think your tank and community and separationa and size of tank for the others. So good news is the Black Knife HASN'T eaten any of the other fish "YET"
Zardo - 2011-05-23
Hey I have a black ghost knife fish, his tail is different to the one shown but I think it's nothing. How do I get him to not hide behind my Fluval 2 filter? Is it ok to feed him dead crickets? Please respond. Thanx

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  • Charlie Roche - 2011-05-24
    Yep it is OK. The documents say wingless crickets and you purchase them.
  • taxman - 2011-07-11
    I have ghost fish in a "L" shape tank. 1 is "odd" shaped due to being injured several times as a youngin. 2 larger ones now about 11 and 12 inch respectively - "Hunchback" only about 6 inches (if I could straighten out) - so your "different tail" could be due to injury or variation to breed. Put more places for GK to hide and will be more likely to leave filter alone - glass pipes work well - can see them, but they think they're hidden - also too much light will send them looking for cover. Re crickets - I have fed mine crickets that have gotten into house, flies, even the occasional moth. I've been keeping GK's for over 15 years and only lost 1 (approx 15 inches) after moving house and using a temporary filter - that died while I was at work. They've all started from less than 2 inches; when purchased.
    Hope that gives you some assistance and reassurance.