Knifefish, Apteronotus (Sternarchus) albifrons,
Related Articles: New
World Knifefishes, Gymnarchus, Notopterids/Clown
Knifefishes, Electrogenic Fishes,
Related FAQs: Knifefish
Selection, BGK FAQs 1, BGK FAQs
2, & FAQs on:
BGK ID, BGK
Behavior, BGK Compatibility,
BGK Systems, BGK
Feeding, BGK Disease, BGK Reproduction, & Knifefishes 1, Knifefishes 2, Knifefish Identification, Knifefish Behavior, Knifefish Compatibility, Knifefish Systems, Knifefish Feeding, Knifefish Disease, Knifefish Reproduction, Electrogenic Fishes, Notopterid Knifefishes
Black Ghost Knife, hlth.,
Hello Wet Web Crew!
I've been using your website since I started fish keeping about 7
months ago. It's very informative, and my go to site when
experiencing problems :-)
However I cannot find an answer to my problem in your FAQ's, or on
any other site. Here's some info on my tank:
55 gallon planted tank with driftwood, and ornaments for hiding.
It's been fully cycled for 6 months.
Fish: 2 Otos, 4 candy cane tetras, 3 Roseline sharks, 2 Bala sharks
(babies only 1.5" long), & 4 pristellas.
My issue is I finally got my beloved Black Ghost Knife a week ago, and
he was doing great right off the bat! Very active, eating well (I
fed him frozen brine shrimp & frozen blood worms),
<Mmm, please see WWM re the latter... and feeding Apteronotids
and he wasn't even hiding as I've read they do a lot even
in my brightly lit aquarium. Then two days ago we found him laying down
on the substrate, looking lifeless so we opened the glass tops and he
perked up, but only for a second and then laid down in one of our
plants. He continued to move throughout the tank but only for
seconds then laid back down. I researched a lot and read that
sometimes they lay down for predatory reasons or to be lazy, which I
found hard to believe. None the less, the next morning he was dead. I
am left devastated. Our water parameters are great, and there was
no signs of infection or disease. I purchased the BGK from a great
aquarium shop too. So I'd like to know why this fish could have
died, are there some special requirements they need that I'm not
aware of? Or did I just get a bad fish?
<Most likely the latter... fishes, aquatic life in general differs
from our/human awareness of tetrapods like birds and mammals... that
show "troubles" almost as soon as they occur. Fishes often
when "challenged", as in damaged in handling, shipping...
I'd like to get another one right away, but I don't want to
wind up with the same issue. It's hard to fight something you
don't understand. What do you think could have caused this death?
Any help would be greatly appreciated.
<Seek a specimen that has been "in stock" for a few weeks
at your dealer... provide it with a glass chimney or such, a container
it can swim into... and see WWM re the diet>
Another issue that arose about 4 days ago, one of our Bala Sharks has a
red bump just behind one of his gills. It's growing in size and
looks like a tumor, it's an internal lump. I'm not sure how to
treat this, and would like your suggestions. I've read medicine
laced flakes are available?
<They are or you can make them>
Does this sound like something treatable?
<Mmm, I'd not treat these small Balas... likely this is a
physical trauma, that will hopefully heal on its own>
What would cause an interior infection like this?
<Again... a (very common) bump, jump into the glass, the top,
decor... this is a very "nervous" minnow species>
Thank you in advance for any help you can provide. I want to give my
fish a healthy happy home.
<Thank you for writing, sharing your concern. Bob Fenner>
Re: Black Ghost Knife 3/2/12
Thank you for the quick reply!
Sorry to be writing about the same topic but I'd like a little
clarification as I intend to get another black ghost knife and I want
to be sure to create a healthy environment for him.
I did already have a clear ghost knife tube in the tank for him, but he
never went in it. He stayed in my skull or under my driftwood but was
very active the entire time we had him. I thought we lucked out with a
super friendly one!
Anyway, I read through your site more as you suggested, and see that
you recommend a cooler water for them, 75degrees maximum and a lot of
<Moderate is fine>
My tank does have a lot of current, I'm running a 70 AquaClear
filter (was thinking about putting another 70 on as well because of the
plants), I have an airstone strip and a fan in the corner that creates
current. So there aren't many dead spots. But I do keep
it on average at 78degrees, so I could lower it if you think my other
fish would be tolerant to the cooler water?
<I'd leave it where it is>
Also I saw that salt can be harmful to them?
I do add one teaspoon of salt to 5 gallons when doing water
<Should be okay... but not of much use. Read here:
and I did a water change three days before my BGK met his fate.
Do you think that's what killed him?
I had salt in the tank already, so it shouldn't have been a
shock. But I don't want to make the same mistake
Plus I got this fish from an aquarium place I trust and he'd been
there for 2 months before I brought him home, and that store uses salt
in their tanks also and keeps the water at 82degrees.
So what do you think?
<Not much more>
On a side note my bala's bump did rupture yesterday and he appears
to be fine. It's scary to see a hole in his side though, I'm
praying he doesn't get an infection in the open wound.
Thanks again for all your help! It's so nice to have a
trusted site for reliable aquarium advice!
<Welcome. Bob Fenner>
Tank Mates for BGK Apteronotus (Sternarchus)
I need some help/ideas, I have a BGK that is currently in a 135 with a
13" Pleco and I am setting up a 180.Since the BGK is nocturnal and
the Pleco doesn't move to much I was hoping for some input on what
WOULD be good tank mates for these two that would be active during the
day? I haven't been able to find a lot of suggestions on this. I
would like something a little more on the unique side but something I
don't have to worry about the BGK eating or it eating/harming the
BGK I really like the BGK (first fish I've ever named)...... Any
suggestions would be GREATLY appreciated.
I'm at a loss.
<Almost any medium to large, non-aggressive, non-nippy schooling
fish would be ideal. Congo Tetras would be excellent! Other choices
might be Silver Dollars, Bleeding Heart Tetras and African Red-Eye
Tetras. Giant Danios might work, but these can be feisty if you
don't keep them in a big group.
I'd avoid Barbs unless you chose species you know won't be
nippy. Tiger Barbs would be bad, but Puntius fasciatus would be fine.
Puntius denisonii can work, but do understand that 25 C/77 F is the
ABSOLUTE upper limit for temperature that this subtropical species
should be kept at. Cheers, Neale.>
Stocking questions 12/7/10
In a compromise with my wonderful wife, I have just got a new 125
gallon aquarium with two emperor 400 filters and an undergravel
As part of the deal I needed to downsize the number of aquariums to the
125 and an established 65 gallon aquarium.
I am seeking advice on stocking these tanks with fish I currently have
and/or any new additions that would be compatible.
My 65 gallon currently has 6 Electric Blue Jack Dempseys all about 3 to
<While the "Electric Blue" morph (or hybrid?) variety of
Rocio octofasciata is somewhat less aggressive than the standard sort,
they're still very aggressive fish. A mated pair could easily cause
problems in this aquarium.
Do read my piece on these fish over at Tropical Fish Finder, here:
As you presumably realise, breeding in captivity is very uncommon,
which is why some suspect they're a hybrid rather than a true
Two Pictus Catfish about 5 inches each and 2 Royal Plecos about 4.5
<Pimelodus pictus is a schooling species, and should really be kept
in groups of 5+ for consistently good results. By contrast, Panaque
nigrolineatus is highly territorial, and there are reliable stories of
males killing one another as well as females. While these are by far my
favourite of the Loricariidae -- my own specimen is about 16 years old
now -- they are normally kept one to a tank, and not alongside any
other Loricariid of similar size or shape (they ignore very different
Loricariids such as whiptails and Otocinclus).>
I was planning on slowing moving these fish to the new 125 gallon.
<Okay, but I still wouldn't expect two P. nigrolineatus to
coexist in this tank. Be aware of the risk of problems, and look out
for signs of fin damage as an early warning that your specimens are
fighting. Serious fighting involves the stronger fish literally flaying
alive the weaker one using its very powerful teeth.>
Understanding that these guys are still growing will this be an
suitable set up?
If more fish could be added, would Tiger Barbs be a suitable addition
or what would you suggest?
<Tiger Barbs wouldn't be my first choice for use alongside any
cichlids, given their nippiness. Giant Danios, Spanner Barbs, Clown
Barbs, Nurse Tetras, or Mexican Tetras would all strike me as better
companions for medium-sized cichlids.>
In the 65 gallon I would like to keep a Black Ghost Knife Fish. I have
read that they can get big and if it got to say 12 inches would the 65
gallon be a suitable home for it?
<Barely do-able. Apteronotus albifrons is a sensitive species, and
the vast majority die prematurely. Ask yourself how many adults
you've ever seen at their full 50 cm/20 inch length? Or living for
10+ years, as should be the case. Outside of public aquaria, it's
rare to see them so large or so old.
Why? Because they need quite specific living conditions that mimic the
cool to middling temperature, oxygen-rich, brisk water currents found
around riffles and rapids in rainforest streams. So while it's true
that A. albifrons tends to stay fairly small in home aquaria,
that's perhaps more a reflection on the fact they die within a
couple of years rather than any sort of "growing to the size of
the tank" malarkey. Take some time to think about their needs,
establish how you're going to provide the right level of water
turnover -- 8-10 times the volume of the tank in turnover per hour --
and also check to make sure you can provide the soft to moderately
hard, slightly acidic to neutral, nitrate-free water chemistry
essential for long-term success. There are other species of Knifefish
with easier requirements, perhaps most notably Xenomystus nigri, a
non-electric species from a completely different family of fish able to
breathe air and naturally found in sluggish rivers. It's smaller
too, 30 cm/12 inches being the absolute tops in terms of size, and most
getting to rather less. By the standards of its family, the
Notopteridae, it's fairly peaceful and can be combined with a
variety of robust tankmates.>
What are good tankmates for a Black Ghost Knife?
<Essentially species that come from similar habitats, with the
provisos that very small fish (such as Mountain Minnows) may be eaten
while competitive bottom feeders (such as loaches and catfish) will
make it difficult for you to keep your Apteronotus properly fed. All
things considered, they are best kept alone, or with a largely
herbivorous catfish species such as Ancistrus dolichopterus. Open water
schooling fish might be chosen, for example Bleeding Heart Tetras,
Silver Hatchetfish, Demasoni Barbs, Swordtails or Australian
Rainbowfish, depending on your water chemistry.>
Thank you for sharing your knowledge and time.
<Glad to help. Cheers, Neale.>
Re: Stocking questions 12/10/10
Thank you for the great information. I will separate the two Royal
Plecos as soon as my 125 gallon has safely cycled. They are both
incredible fish and do not want them to hurt each other. I will also
add some additional Pictus Catfish. If I may ask a few more questions
about the Electric Blue Jack Dempseys? Will a 6 foot 125 gallon tank be
enough aquarium for Royal Pleco and Pictus to thrive and also allow the
Jack Dempseys to set up their territories. These fish are all young and
will grow older together, will this lessen aggression from the Jack
Dempseys? So far there have been no aggression issues but the Jack
Dempseys are all of equal size or smaller then the other fish. Once
again thank you for your help and merry Christmas to you and yours.
<Jack Dempseys aren't really community fish, and while they
could coexist with a larger Panaque nigriventris, given sufficient
hiding places, I would not mix them Pimelodus pictus. As I hope you
realise, Pimelodus pictus are quite peaceful schooling fish and
they're easily harassed by aggressive cichlids as well as nippy
tankmates. Good companions are things like Silver Dollars, Australian
Rainbowfish, Severums, and so on. They also prefer soft water, whereas
JDs need hard, alkaline water. Now, Electric Blue Jack
Dempseys add a further level of complexity to the situation. While they
do seem to be marginally less aggressive than regular JDs, this may be
because they're rather inbred animals with poor quality genes. One
of the things that people have observed with EBJDs is their delicacy.
They just aren't hardy fish and whatever inbreeding was required to
create them, thanks to their popularity, they're getting worse as
people breed them to a price rather than a quality. Personally, I
wouldn't touch them with a bargepole,
but if you do want to keep them, at least make an effort to get good
quality stock, rear them in their own environment away from other fish,
and ensure water chemistry, water temperature and water quality
(including nitrate) are ideal for the species. There are much better
blue cichlids you might keep, for example Blue Acara, these latter
getting along perfectly well with Pimelodus and Panaque species.
Perhaps not so garish in their shade of blue, but far more elegant and
natural. Cheers, Neale.>
Re: Brown knife fish... Now Black Ghost Apteronotid
Sorry for asking so many Questions but, by the way do you know where I
can purchase a Black Ghost Knife Fish online? my local pet store is
complete crap they sell a 4 inch one for 50$..
<With these fish, I'd strongly suggest buying one in person. You
WANT to see the condition of the fish: it should be active, with a
plump belly, no sign of fin erosion or disease. Don't forget, you
can't mix Apteronotus species or specimens in one tank! All
electric fish "jam" each other when kept together. Unless you
have enough space for a large (5+ specimens) group, keep one electric
fish per tank, and only one species per tank regardless.