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!
Latest Animal Stories
Linda - 2013-07-12
I have a tank that is 25 gallons, I have 4 BGK in this tank, I love this type of fish and decided to have only this fish. First of all I introduced them to the tank all at once! (all 4) the only other thing in this tank is gravel and 2 ghost houses, (no plants at all) I do have a dual light on this tank however I have disconnected the bright light and only use the black light. I only explain this because everyone has told me that my tank was too small, and that I could only have a small BGK in this tank. I simply love this fish and find them quite hardy in raising so I decided to try and have only this type of fish. During purchasing I made absolute certain to get them all the same size. (rather large) happy to say that all is well! A little chasing, which is fun to watch, but no fighting what so ever. I only feed them frozen blood worms, at first twice a day, but now I feed them only once a day. Is this a miracle or what?! This is contrary to everything that I have been told and read about them

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  • Linda - 2014-07-19
    Hey Linda, this is my very same story. I have always had 3 in my tank, which is 25 gallons. which everyone says is small.They are now 2 yrs old and I have had no problems with them being aggressive, except for a bit of chasing. I feed them only bloodworms, and have also disconnected the brighter light, and have 2 clear tubes in the tank with white gravel nothing else is in the tank.I feed them a cube of bloodworns every other day.I think that they too have their own personalities, but I would never incorporate smaller fish, that said any larger fish will bully a smaller one.
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Bruce - 2014-02-12
I have a 300mm BGK which I have grown 35mm youngster I bought at the local pet store. I have had him just over two years now living in an comfortably in an Aqua-One 980 (about 230 litres) tank with Phantom glass catfish, Black Widow Tetra's and bristle-nose catfish. He is a fantastic fish spending a lot of time upside in his 100mm diameter clear plastic tube hiding in full view from the world.

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Zoey - 2014-02-05
Please can some one help me my cousin got a angel fish 2day and her black knife keeps attacking it is this normal?

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  • Clarice Brough - 2014-02-05
    A Black Ghost Knife can get aggressive with its own or similar species, possibly like those nice flowing fins of the angel! Making sure the tank isn't too small, these guys reach 20' in length, and that there are plenty of hiding placed all around the tank can help.
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david - 2011-06-12
Are Rams compatible with Heckel Discus, Altum (wild) Angelfish, and Black Ghost Knifefish? How about with Silver Dollars?

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  • Charlie Roche - 2011-06-13
    The Knifefish needs a minimum of a 100 gallon tank on his own. They are beautiful but they get huge and he will most likely eat the others.
  • cody - 2013-02-24
    The angel fish isn't recommended but you may try with a knife fish all depends on you tank size to oh and for the discus. Alot of people may tell you to keep them in a single species tank and they need different water phlevels in their tank.
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kye turnbull - 2013-05-14
please help my bgkf tail has rotted away! i think its to late its rotted rite down to the first white stripe! we are treating it now, my brother will cry if it dies

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  • kye turnbull - 2013-05-14
    this all happend over night
  • Clarice Brough - 2013-05-14
    That is very fast, it might be a tankmate is biting him. I'd suggest you watch the tank closely to see if you have a culprit in there that is being aggressive as well.
  • kye turnbull - 2013-05-15
    Pprobably the tandanus! It's always biting fins when its water is low quality (that is one of the reasons I can tell when I need a water change).
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kye turnbull - 2013-05-12
is it usual for a 10 cm black ghost knife to eat a 5 cm gambusia affins?

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  • Jeremy Roche - 2013-05-12
    Some can be aggressive and will eat anything that will fit in their mouth.
  • kye turnbull - 2013-05-12
    mine is very easily scarred and is picky on what it eats it only ate one
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Melvyn Williams - 2013-04-30
Thanks for your advice regarding my BGK. I believe I will leave well enough alone for the moment. I purchased 2-1' Angel Fish yesterday. When I admired my tank in the morning, they had both 'given up the ghost'. They were fine last night, I always have the water tested before I purchase anything and it was fine. They had not been eaten so I want to refrain from the BGK being the culprit, however, I have 2-2' black sharks, who have now recognized their aggressiveness. Could they have become the new vultures of my tank? And if that may be the case will this change the overall character of my community tank of assorted loaches? Your assistance is appreciated. One more thing, I have some feeders (6) who managed to survive and are now 5' and about 1/2' thick that nip at each other. They started out as 1' last May. How big will they get?! WHO EAT MY ANGELFISH!!!

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  • Clarice Brough - 2013-05-01
    I bet the Black sharks are the culprits who got your angelfish. But on a positive note, if you are keeping a community loach tank, you should be fine... but Angelfish aren't going to do so well. On your feeder fish, I'm assuming you mean goldfish by the size you've described of 5'. They can get up to 14' on average though, so will get to be big fish. The tank will  need 20 gallons minimum for each of the goldfish, plus plenty of space for your Black Ghost Knife, so you may have to consider getting a huge tank - or maybe moving somebody! Good luck:)
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Melvyn Williams - 2013-04-28
I am so glad I found your site. I have owned BGKs for years and have just been facinated by them. My largest was about 18' in a 75 gallon tank. Anyway. I was always told you could only have one in the same tank for various reasons. Recently, a local retail dealer told me that you can have more than one in a tank, only you can not have two. Given all the comments and breeding scenarios on your site, can you shed some light on this for me. I have 150 gallon community tank and my recent BGK (Ribbon)is approximately 6' and has live comfortably with every one for about six months. Yes, I have occassionally noticed a fish or two mia, however, innocent until proven guilty (some of my community fishes have interesting traits). So I would like to purchase two more if that is possible. Could you give me your opinion please. For the record, I have a variety of Loaches (Clowns 5-2', [Blues, Zebras and Poka Dot 2 each sapprox 2'] Botias, Kulis 3-2') some green corys 2-2', black sharks 2-3', a spotted raphael cat 1- 3', golden sharks 2-2' NOW, angels 3-3' and assorted plecos4-2'-5'. Thanks.

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  • Clarice Brough - 2013-04-28
    The Black Ghost Knives are fascinating fish, and one of my favorites too. These fish don't like others of their own kind though, and are known to fight. Sometimes if a tank is very large, with lots of rocks and decor for fish to have their own territories and out of the line of site of those they don't like, aggressive fish can be kept in the same tank. But mxing them is a really tough call. You do have a large tank, but because these are also large fish  the tank isn't really so large for their needs. If you try mixing more than one, just be ready to separate them into their own tanks if they don't settle in together.
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Teresa Sloan - 2013-04-24
We just bought a BGKF last night. I had seen him the previous week-end and fell in love. We also bought a silver-tipped shark.  My question is more in regards to the filter system. When my husband started to leave for work this morning, we found we had a casualty last night in that (we think) the ghost had gotten too close to the filter and was sucked up. I don't think the filter end sits that close to the bottom of the aquarium, and he was so happy lying among the rocks. The shark seems fine, but I'm just wondering if the ghost did swim too close to the filter and got caught up in the suction or if perhaps something else had happened and it was just his remains that got caught there. We've had smaller fish in there with no problems of them being caught up in the filter.

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  • Clarice Brough - 2013-04-24
    So sorry to hear about your casualty. Iif your filter is really robust, with a lot of suction, you might want to cover it with some aquarium filter foam. That will keep any fish from getting sucked up.
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kye turnbull - 2013-04-10
my black ghost knife wont come out of his tunnel! he just stays in there day and night,is this usual, theirs plants to dim the light and 2 tunnels and i feed live and frozen foods almost every day!

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  • Jeremy Roche - 2013-04-11
    That is pretty normal for them.  More then likely moves around when no movement in room.
  • kye turnbull - 2013-04-12
    all it needed was incouagement! i sang wooo go ghosty woooo ghosty wooo go ghosty! and he came out :D
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