Question regarding Knifefish and tank mates

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Cyradis4

Feeder Fish
MFK Member
Oct 9, 2019
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Good morning,

A while ago I got a Knife fish and a ZigZag eel. They were really small, so they've lived happily together in a 30 gallon tank since I got them. They are starting to reach a size where I'm considering a new home for them.

I have a 180 gallon tank which will soon have a trio of 12"+ Endlicheris, a pair of 11" Delhizis, and a 11-12" Venezuelan Pike.

Is it safe to add the 8" Black Ghost Knife and 8"(ish) ZigZag eel to that tank now? Is it safe to add them in ever? The Pike is a pike: he's got attitude problems.

If its not safe to add the Black Ghost Knife / Eel to the Bichir / Pike tank, can I add it to a planted tank with Discus fish in it?

Thank you!
C4.
 
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Good morning,

A while ago I got a Knife fish and a ZigZag eel. They were really small, so they've lived happily together in a 30 gallon tank since I got them. They are starting to reach a size where I'm considering a new home for them.

I have a 180 gallon tank which will soon have a trio of 12"+ Endlicheris, a pair of 11" Delhizis, and a 11-12" Venezuelan Pike.

Is it safe to add the 8" Black Ghost Knife and 8"(ish) ZigZag eel to that tank now? Is it safe to add them in ever? The Pike is a pike: he's got attitude problems.

If its not safe to add the Black Ghost Knife / Eel to the Bichir / Pike tank, can I add it to a planted tank with Discus fish in it?

Thank you!
C4.

I've personally tried a Black Ghost Knife with Polypterus and one of the bichir bit his tail off . Never tried any Eel species with Polypterus. If eel is slim enough to fit in the Bichir mouth wouldn't risk it.
 
Good morning,

A while ago I got a Knife fish and a ZigZag eel. They were really small, so they've lived happily together in a 30 gallon tank since I got them. They are starting to reach a size where I'm considering a new home for them.

I have a 180 gallon tank which will soon have a trio of 12"+ Endlicheris, a pair of 11" Delhizis, and a 11-12" Venezuelan Pike.

Is it safe to add the 8" Black Ghost Knife and 8"(ish) ZigZag eel to that tank now? Is it safe to add them in ever? The Pike is a pike: he's got attitude problems.

If its not safe to add the Black Ghost Knife / Eel to the Bichir / Pike tank, can I add it to a planted tank with Discus fish in it?

Thank you!
C4.

I tried keeping a black ghost knife with an endlicheri bichir once. The bichir quickly outgrew the knife and ate it. As far as eels go, a fire eel or tire track would work with the endlicheri bichir providing the eel is larger. The zig zag would most likely get eaten.

In the past, I've successfully kept a senegal bichir with a black ghost knife long term. I bought the knife larger than the bichir and grew them together. Since senegals and delhezis grow close in size, I suspect this method would work with a BGK and a delhezi. In your case, though, at the size your delhezis are now, they may kill the smaller knife.

And finally, the pike may be too aggressive for the BGK.
 
Last edited:
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I have a 9 inch fire eel with a 8 inch Endlicheri and a 8-9 inch zebra pike. So far so good. And I’ve had either the endli or zebra kill a jardini in 3 days. Eels are good at staying low key, they hide and mind their own business. I feel like a ghost knifes while elusive, have a bit of target as easy pray on their back and it seems other fish know it. Just make sure your eel is thick enough to avoid being a snack and has places to hide it can only get into.

This is Fred. Fred has a few exit holes and likes to observe the other fish from above ? he keeps his head out throughout the day and hunts for food with the lights sunrise/sunset. Fred’s a survivor.

CA3DB460-B59B-4922-AB99-AC0FB318E421.png
 
it would be so cool to make a amazon themed aquarium with black ghost knifefish and red bellies
probably would need a large aquarium though
 
Knife cannot mix with piranhas. Knife is too slow moving and calm. Piranhas can and will tear it to pieces. Generally, piranhas should be left alone or with fish fast, armored, or dangerous enough to survive. Only fish that truly fits the bill for a piranha tankmate is a banded leporinus (I still don’t recommend it).
I would love to see piranhas with a knife, but it just isn’t possible.
If you want the piranha effect, look into red hook silver dollars. They look like small pacu and should be fine with the knife.
 
Ok so, no BGK with the Bichirs, unless I split the Delhizis' into a different tank.

Now, can the BGK be kept in a planted Discus tank? And would it eat the cory cats? The Discus were bred in 80F water, and live in the same water as the BGK.
 
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