Knifefish, Apteronotus (Sternarchus) albifrons, Disease/Health
New World Knifefishes,
BGK Disease 1,
BGK Disease 2, BGK Disease 4,
BGK Disease by Category:
BGK Reproduction, &
Black ghost knife may be sick 4/19/19
My black ghost knife has recently transferred into a new tank but has so far
been comfortable and seems happy in his new home. He ate a few fish within the
first few days of being in the tank but otherwise has had a steady diet.
<Please do not use feeder fish! Indeed, eating any sort of live fish, whether
cheap feeders or pet fish massively increases the risk of health problems.>
Recently I checked on him at night when he was active and his skin appears to be
a greyish colour with white splotches. It's like that on both sides of his body.
Is this normal?
And if not how can I treat it, he is a very important thing in my life and I
would do anything to make him better if he is sick. Pleas help
<Grey patches of slime usually indicating some type of irritation to the skin.
It's similar to a human getting an inflammation or rash. And like a rash, it's a
symptom rather than a specific disease. Environmental stress can cause this, but
more often it's some type of infection. Costia (Ichthyobodo) is a common cause,
and often called Slime Disease because of this. Various medications exist for
this; I like eSHa 2000, but something like ParaGuard would be a good
alternative. Seachem recommend starting with one-half or even one-quarter
dosages with sensitive fish, and only increasing upwards to the full dose
as/when require and if you're comfortable the fish is tolerating the medicine
well. I'd support that approach, given the type of fish you're keeping here.
Black ghost knife fish, glass catfish, and neon tetras
Thank you for your website. It’s very informative.
<Hello Vicki, and thanks for the kind words. However, sending 20 MB of
attachments completely messed up our email box, which causes some people's
messages to be sent back to them as undeliverable. We do politely ask people
keep attachments down to a minimum size, around 500 kB for images, by resizing
them in a graphics application of their choice.>
I have queries about 3 fish species.
I have a BGK (see photos attached). Out of its anus this pink growth has
suddenly appeared (happened 4 days ago). At times what appears to be
faeces still is coming out so don’t think it’s a blockage. It’s behaviour
remains unchanged. It’s still appears happy and is swimming around and eating.
I’ve read on your website not to feed it blood worms (unsure why?). What else
can we feed it other than bloodworms, brine shrimp, and daphnia? I have been
feeding it bloodworms and brine shrimp and it has also been eating vegetarian
food I put out for my bottom feeders (such as spinach, broccoli, carrot, shelled
peas, couchette, cucumber, and pellets) and flakes. I apologise for the grainy
photos but it is very difficult to get clear images from a fish tank.
<I'm not sure this is the anus of the fish. Looks a bit far forward. The anus
should be well past the gill covers, and close to the front of the anal fin.
<<Mmm; actually; this knifefish, and others, do have a "jugular" placed
cloaca... "anus". RMF>>
if it is what you say it is -- and you can see the fish better than me! --
then a prolapse may be the issue here. Various reasons for this, but
often internal protozoan parasites or worms at the cause. Medicating with
Metronidazole alongside a good antibiotic such as Nitrofuran would be my first
move. Deworming is worth a shot, for example with PraziPro. Sometimes prolapses
are triggered by dietary shortcomings, so review this aspect alongside
One of my glass catfish appears to have white spot? I’ve been
treating it with Melafix and Pimafix for 6 days and it remains unchanged.
Same with the neon tetras who have had continuous growths and damage to
their fins since we got them (8 weeks or so). We’ve been treating them with
Melafix and Pimafix in a hospital tank but they don’t seem to be getting better.
<These are both somewhere on a sale from unreliable to useless.>
We’ve even tried “tonic” a mixture of Methylene blue mixed with malachite green.
It didn’t work.
<Indeed not; neither of these is considered first-rate anti-Whitespot
medications. The old salt/heat method works well if this truly is Whitespot (2
gram salt/litre water, plus water temperature raised to 28 C) but many aquarists
simply prefer to use a commercial anti-Whitespot medication, such as eSHa EXIT.>
We have even tried feeding them with their flakes soaked in Seachem garlic
guard. We don’t want to keep treating our fish and would like these issues
<Again, nothing about garlic treats Whitespot.>
Other fish that live with the BKF and glass catfish are Plecos, Kuhli loaches,
black neons, clown loaches, chain loaches, striata loaches, varies Gourami,
female Betta, golden tetras, albino shark, bristle nose catfish, and Colchis
blue (I think they are called).
<No idea what that last fish might be! But in any case, Black Ghost Knifefish,
most catfish, and most loaches are very intolerant of copper and formalin, so
choose medications very carefully. The salt/heat treatment is safe with them, as
are Metronidazole and true antibiotics.>
We use RO DI water and all our parameters are perfect.
<I'd prefer the actual parameters over your interpretations, to be honest. But
providing you have fairly soft to middling water chemistry (1-12 degrees dH, pH
6.5-7.5) this mix of fish should be fine. I trust you are not using pure RO
water, but are adding something to it, whether hard tap water or commercial
Discus buffer? Straight RO water is not helpful.>
Tanks are well oxygenated as well.
Any help you can give will be greatly appreciated.
<You're welcome, Neale.>
Re: Black ghost knife fish, glass catfish, and neon tetras
Thank you for your prompt reply. I apologise for sending through large
photos. Will know for next time.
I appreciate your help.
<You are most welcome! Good luck, Neale.>
Copper poisoned BGK 3/5/18
I made a massive rookie mistake, and used snail rid (copper based) in my
community tank which includes my BGK. I did the initial treatment and followed
up 3days later. 2 days after I noticed my ghost knife looking sick, I did a
frantic online search and that’s when I discovered that copper is toxic to them.
I immediately did a water change and picked out any remaining snail shells,
added two aerators. I’m relatively new to all this so not sure what else I need
to do. BGK is swimming vertically in the corner where the filter is, doesn’t
take food. Any advice would be greatly appreciated.
<I would run activated carbon in your filter system... to remove residual copper
and improve water quality, and add Methylene Blue to the extent that the water
is quite blue in color... no dosage other than this recommendation. This will
act as a mild bacteriostatic as well as improve dissolved oxygen and cut down
light penetration. >
<Welcome. Bob Fenner>
Re: Copper poisoned BGK 3/5/18
Thank you so much for your reply and advice! Will let you know how I go.
<Ah, good. Thank you. BobF>