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FAQs on Black Ghost Knifefish, Apteronotus (Sternarchus) albifrons, Selection

Related Articles: New World Knifefishes, GymnarchusNotopterids/Clown KnifefishesElectrogenic 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 (Clowns...),


Black Ghost Knife, hlth., stkg.    3/1/12
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 :-)
<Ah good>
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.
PH- 7.4
Ammonia- 0
Nitrite- 0
Nitrate- 20
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 period>
 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... days later>
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 current?
<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?
<Can be>
  I do add one teaspoon of salt to 5 gallons when doing water changes,
<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 again. 
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) albifrons    11/15/11
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 filter.
As part of the deal I needed to downsize the number of aquariums to the 125 and an established 65 gallon aquarium.
<Fair enough.>
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 3.5 inches.
<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 variety.>
Two Pictus Catfish about 5 inches each and 2 Royal Plecos about 4.5 inches each.
<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?
<See above.>
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 sel.    12/31/09
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.
Cheers, Neale.>

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