# Ghost Knife questions.



## Ghost Knife (Jun 1, 2011)

Hi, I'm pretty new to the whole fish thing here so I didn't realize the people at our local pet store either aren't the smartest, or assumed I knew more then I did. My girlfriend got a tank recently, so I went and bought a few fish for myself to throw in the tank. One was a ghost knife fish only about 2.5", 3" right now maybe but they failed to mention that I will need a larger tank for him because he can grow up to 18" I hear. 

So, I was wondering if anyone has experience with a ghost knife and what size of a tank would be appropriate for him. I also want to have a few other fish to go in that tank as well so I was wondering what fish would go well with him. I was hoping that my red tail black shark and blue gourami I bought would work. I hear those two are fine in our tank as it is, so if not, whatever but I was also interested in the denison barbs and either clown loach's or yoyo loach's. What kind of algae eaters I would need too. 

I just want to know as much as I can before its to late and I have to wing it, which reminds me, what is their rate of growth? Do I have to deal with this right quick, or do they take a significant amount of time to grow? (A year say...)

Anyways, any info would be appreciated because i r fish rookie and don't want them to get eaten or sick or anything. Later fish peoples.


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## taureandragon76 (Apr 21, 2010)

Most pet stores are not going to ask what size of tank you have or let you know how big the fish is, generally it is up to the buyer to do their research first. Can save alot of hassle for oneself by researching before buying. I don't have much experience with knife fish but do know that the first question others will ask is the size of your tank.


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## Ghost Knife (Jun 1, 2011)

They did ask the size of the tank, which is a 45 gallon, and how many fish in there (about two dozen at this point), and that was the end of it really. So I got him thinking it would be fine, not realizing how big they get. So the first thing I need to know is how big a tank I should get before I start worrying about the other details.


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## spit.fire (Jan 3, 2011)

for a full size ghost knife they do best in a 90 gallon or larger tank, generally in an aquarium they wont get bigger than 12 inches long. 
also they dont do good in groups or pairs

PS: if it gets to big i'd have no problem taking him off your hands


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## King-eL (Apr 21, 2010)

spit.fire said:


> for a full size ghost knife they do best in a 90 gallon or larger tank, generally in an aquarium they wont get bigger than 12 inches long.
> also they dont do good in groups or pairs
> 
> PS: if it gets to big i'd have no problem taking him off your hands


Not bigger than 12"? I managed to grow a black ghsot knife in about 4 years in a 90g tank at 19". In 7 years it grew to 23" in my 210g.

@ Ghost Knife
There are hundreds of species of ghost knives and the black ghost knife and brown ghost knife are common in the hobby. Please be more specific on which one you have. Both have the same care but requires differebt tank size. The brown ghost knife have longer snout and max out at 9". The black ghost knife have darker color and blunt snout and max out t 2 feet.


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## Danw (Feb 26, 2011)

my BGK's live in a 125g and the largest is about 14 inches and hes still growing. i have a 3 of them in my 125 and they get along just fine. they just stay out of each others way. in my limited experience they seem to just need space. also dont house them with tetras or smallers companions as they will quickly disappear. your gourami will be fine but i dont know about the shark probably fine as well because bgk are extremely nocturnal. your bgk should be fine in your 45g for roughly half a year. but in a year he will be around 10-12 inches. got any other questions shoot me a pm.


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## spit.fire (Jan 3, 2011)

King-eL said:


> Not bigger than 12"? I managed to grow a black ghsot knife in about 4 years in a 90g tank at 19". In 7 years it grew to 23" in my 210g.
> 
> @ Ghost Knife
> There are hundreds of species of ghost knives and the black ghost knife and brown ghost knife are common in the hobby. Please be more specific on which one you have. Both have the same care but requires differebt tank size. The brown ghost knife have longer snout and max out at 9". The black ghost knife have darker color and blunt snout and max out t 2 feet.


i said generally....

generally people put them in to small of a tank and it stunts them


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## Ghost Knife (Jun 1, 2011)

Wow, thanks guys, I think I have what I need to know at the moment. I think I will start looking into 120g tanks, and sooner then later. Even if he lasts half a year or so in the tank I have, it sounds like he will soon grow large enough to eat up the small guys I have in there. I will look into compatability with the redtail black shark then. Both get along just fine now (and live in the same general area in my tank) but I will see how that changes as they grow. It is a black ghost knife as well, just to clarify.

The little guy is also gonna need a bigger pirate ship now too


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## LikeItLow (Jan 11, 2011)

i had my BGK in a 29 for 4.5 years and he grew to about 8 or 9 inches now hes in a 65 and eating all my tetras lol. i have a rainow shark with my ghost and from what i can tell they get along ok but time will tell. i had three siamese elgea eaters that were close to 2 inches long dissapear after i put the knife in lol. so even if they are big, if they are skinny and he thinks they will fit he will get them.


aslo does anyone one have pictures of monster BGK's? i hear the aquarium has 2 big ones. ive never seeen one bigger than mine. youtube/google images arent much help on being able to decifer how big they really are.


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## -DC- (Apr 21, 2010)

Agreed i'd also love too see some pic's of a BGK over 16"! I've read of them getting that big but never see bigger one's , i'd love to get my hands on an 18-20" BGK!


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## Smiladon (Apr 23, 2010)

Ghost Knife said:


> Wow, thanks guys, I think I have what I need to know at the moment. I think I will start looking into 120g tanks, and sooner then later. Even if he lasts half a year or so in the tank I have, it sounds like he will soon grow large enough to eat up the small guys I have in there. I will look into compatability with the redtail black shark then. Both get along just fine now (and live in the same general area in my tank) but I will see how that changes as they grow. It is a black ghost knife as well, just to clarify.
> 
> The little guy is also gonna need a bigger pirate ship now too


Go for a 6ft tank if you can afford the price and space. It allows you a wide variety of choices of fish to choose from.
There is a guy selling his 125Gallon for $500 in the classified right now 

Good luck with your ghost knife.


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## pdoutaz (May 13, 2010)

I too failed to do my research - had 5 4+ inch BGK in my 120 for about 3 months, finally realized I was missing MOST of my smaller fish - swords, platties, and tetras.
Amazing fish, but carefull of the tankmakes


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## Danw (Feb 26, 2011)

YouTube - ‪Black ghost knifefish / Weißstirn-Messerfisch @ Zoo Duisburg [3/17]‬‏ this the biggest BGK ive seen to date must be 20 inches. maybe a bit smaller, hard to estimate but hes massive!!!


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## King-eL (Apr 21, 2010)

Danw said:


> YouTube - ‪Black ghost knifefish / Weißstirn-Messerfisch @ Zoo Duisburg [3/17]‬‏ this the biggest BGK ive seen to date must be 20 inches. maybe a bit smaller, hard to estimate but hes massive!!!


Looking at the headshape and thickness of the body.... I would say not 20". Looks smaller than 14-15".


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## Danw (Feb 26, 2011)

King-eL said:


> Looking at the headshape and thickness of the body.... I would say not 20". Looks smaller than 14-15".


upon second viewing i would have to agree with you. not as thick as i originally thought.
in this vid, YouTube - ‪Biggest Black Ghost Knife Fish ( Adult Size )‬‏ how big do you think the big one in this is??


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## King-eL (Apr 21, 2010)

Danw said:


> upon second viewing i would have to agree with you. not as thick as i originally thought.
> in this vid, YouTube - ‪Biggest Black Ghost Knife Fish ( Adult Size )‬‏ how big do you think the big one in this is??


Around 12"+.


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## LikeItLow (Jan 11, 2011)

yeah the ones in the second vid look to be just around 11 or 12 inches.

heres a fun fact. i found out today that my 9 inch knife can turn its self around in a 4" diameter tube. real flexible fish lol


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## firsttenor (Jul 7, 2010)

They seem to grow very slowly, mine only grew to one foot after 3 years. Then it started to grow even slower, about an inch per year.


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