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FAQs on Knifefish Behavior

Related Articles: Knifefishes, GymnarchusBlack Ghost Knife, Electrogenic Fishes,

Related FAQs: BGK Behavior, Knifefishes 1, Knifefishes 2, Knifefish Identification, Knifefish Compatibility, Knifefish Selection, Knifefish Systems, Knifefish Feeding, Knifefish Disease, Knifefish Reproduction, Electrogenic Fishes,


BGK suddenly shy  11/12/07 Hello Crew, I've had a BGK for 8 months now. He lives in a 55 gallon tank with 2 clown loaches, 3 discus, 2 rams, and a golden nugget Plec, with loads and loads of plants. I do weekly water changes, and water conditions are almost perfect. ammonia 0, nitrite 0, nitrate trace. People always comment on how crystal clear my water looks. He's been very healthy and happy, and growing slowly. There are several hiding places for him but he has taken up home with the 2 clown loaches in a black tube. <Predictably> The three of them swim about looking for food during the day as well as when the lights go out. As soon as I drop food in, those three are the first on the scene playing with each other and eating as fast as they can, its so cute to watch. <Ditto> But in the last 3 weeks or so, the BGK has stopped coming out. He just stays in the tube wiggling about. At feeding time only the loaches come out. I'm very careful with over feeding so the food I put in is always all gone within ten minutes. So I'm 99.9% sure the BGK hasn't eaten in 3 weeks!! <Mmm, is eating something, assuredly... Perhaps you have other food... live worms and such, living in the gravel at this point> Is it normal for these fish to suddenly change their behavior? <Does happen> Today, I fed my discus live bloodworm as a treat, one worm landed in front of the hiding tube and the BGK stuck his head out ate it and went back in. My question is, how could a friendly full of life BGK suddenly become a scaredy cat? there has been no changes, no new tank mates, no change in feeding schedules. My tank is always in view, and he never comes out, day or night. Can there be a chance of illness with him? What can I do? thanking you in advanced Freddie <If I had to guess... I'd say that the most likely possibility is that your Discus are getting larger, perhaps showing a bit of aggression toward this Apteronotid... Do try to spend a bit more time in front of the tank to observe... If two do pair off, there may be trouble for all the other fishes here. I might try some cultured black worms (tubificids) to urge this Knife's return to feeding. Bob Fenner>

Black Ghost Knife, Borg-Style - 02/09/2007 Is this strange behavior? Hi, I bought a black ghost knife fish yesterday morning, assimilated him/her(?) <"Resistance is futile"> into the tank, and almost from the get go it started to hide inside of this Chinese tower that has open spaces toward the rocks & just lays there. <Mmm, what this species does during the day/light hours> I know the majority of fish have to move to survive, but he literally lays on his side, gills moving. <Natural> When I reach in and move him <Don't do this... "they don't like that"> he starts swimming again and I can get him to go into his tube. Right now he's swimming in the tube, has been for a few hours. I noticed after studying him that he seems to have an injured fin. The one side is full and moves, but the other is smaller, more straggly and doesn't move much. Could it be that he's getting tired? <Mmm, no> I fed him 1/2 a chunk of a bloodworm cube last night and he came out 2 eat. Also the guy @ the pet store said to feed him every other day. Is that correct, or should it be every day? <... please see...> I'd sincerely like your opinion, so I know if I should take him back & get a different one, or if these are some normal behaviors. They are beautiful fish and I really want him to be okay, but its a roll of the dice w/ any animals in captivity. Thanks you so much! Lisa <Here: http://wetwebmedia.com/FWSubWebIndex/knifebehfaqs.htm and the linked files above. Bob Fenner>

Black Ghost knife fish ate my Betta?  11/22/05 Hi, <Howdy> I wonder if you can help? <Perhaps> I purchased a Black Ghost knife fish after being very intrigued in him at my local store( and only after being assured by my local fish store that they are a community fish and quite harmless). <...?> I also brought a few Cardinal tetras at the same time. <As food items?> All was well for about 5hrs until I noticed that one of my tetras was dead and had its tail missing.. the next day my Fighter fish was dead and had his fins totally stripped as well as another Tetra. I've checked my water and everything seems in order so I don't believe that bad water quality was to blame for this, I was wondering if my Ghost Knife could have done this? Cheers, Steve. <Yes... Bob Fenner> 

Black Ghost Knifefish, Quarantine - 10/17/2005 Greetings and salutations! I would like some advice on caring for a Black Ghost Knife. I brought home a healthy specimen at around noon, and put him in a 10 gallon quarantine. <Ah, good. Quarantine is essential with new stock.> He was a beautiful deep black with off-white markings, roughly 4 inches. It's now 2 AM and the entire front part of his body has faded to a silvery color. <Go to sleep! Actually, he could just be fading to more nocturnal colors.... though I cannot recall having seen them change to lighter colors at night - but many fish do.> It's as if his black is fading completely away! My QT water parameters: Nitrite/Ammonia-0ppm, Nitrate-10ppm, temp-78F, slightly hard water, pH 7.2. <What pH was he in at the store? He could be suffering from a bit of a shock from change in pH and hardness.... They hail from waters of low-ish pH and low-ish hardness, so this may be part of the issue. At this point, however, I would not change what you have - a steady pH is FAR more essential than a "perfect" pH.> The tank is bare but for 2 PVC pipes. <Large enough for him to enter and hide in?> The tank is in a private room, and the light is off. The fish is swimming "normally" (like an excitable drunk). Fed some frozen brine shrimp earlier, but he seemed to be spitting them out. <He may not eat for a day or so.... but likely you will need to start him on live foods. I could be mistaken, but I believe these animals are only wild-caught and not at all bred in captivity.> I read that these fish are very sensitive and their rich black color may fade due to stress, but I was wondering how common it is for this fish to fade so drastically in this short period of time!!! <Mm, 14 hours isn't really a short period of time.... a fish turning pale at night can do so in minutes. 14 hours is more than plenty of time for the fish to get stressed, as well.> I will keep a sharp eye (I can't sleep the way it is). Should I add a bit of salt? <No.> Stress-zyme? <No.> Is there possibly a metal in the water that Aqua-safe is not removing? <Not likely that this is what's harming the animal, if anything. I would suspect a poor reaction to a sudden change in pH above all else.> I always appreciate your help, thank you in advance. ~M <All the best, -Sabrina>

Training a black ghost knife fish  9/22/05 Dear Mr.  Fenner, I have a black ghost knife fish that I have had for a month.  He is now about 7" long and very healthy.  He eats flakes in the morning and at  night, occasionally I give him some freeze-dried Tubifex worms.  What I  would like to know is how you teach them to eat out of your hand. He seems to be  a smart one he figured out the flakes were edible on his own.  If you know  how to do this I would really appreciate it. Thanks for your  help, MDM <Try feeding small amounts of meatier foods, more frequently, particularly just with some light on outside the tank (not in... too bright). Takes time, patience. Bob Fenner>

Just general random questions about Knifefish... heh Hey there! First off, I'd like to say that I'm completely Wowed by your extensive and totally awesome information and help on all sorts of fish and such. It's been a great help to me, and quite interesting to read (heh, I'm a bit dorky =P) <You're in good company here> I've had fish for all my life really, and I'm always trying new stuff, so naturally, when I spotted an odd looking fish, I snatched him up right away. Probably not the most brilliant of moves, but the shopkeeper assured me that he was what I could handle properly. (we've known each other for some time...) He sold him as a "Chocolate Ghost Knifefish". Upon proper research.... I couldn't find a single thing on them, really. ^^" I can't quite determine the species of fish he is (or she really, I haven't found many websites that are too helpful with sexing Knifefish.), but he LOOKS like a Black ghost knife... but with a longer face, brown-ish, and a yellow stripe and a white dot for a tail. He doesn't match up with Brown Knifefish either, he just...isn't. Are there such things as Chocolate Ghost Knives, or is he just a special brown? <Mmm, there are a few species of apteronotids this could be. Most often sold is Sternarchella schotti: http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=48027&genusname=Sternarchella&speciesname=schotti> It's been a good couple months since we got him, and he seems very healthy and quite lively and happy. We've been feeding him frozen blood worms, but I've recently wanted to change it up a bit, too. I heard full grown brine shrimp aren't particularly nutritious though...can we feed just hatched, or is that too small/meager to last them? <The latter> I heard frozen krill was a good choice; compared to blood worms, where does that stand? <A mix of worms, insect larvae, crustaceans... live, or frozen/defrosted will do> When there's a downpour around our area, we often can find earthworms and such wriggling about, and our old fish gobble those up. However, we've been concerned that they may either lack nutrition, or possibly still have chemicals from landscaping/lawn work, is that a concern? <Yes> We often eat shrimp and seafood at my house, and though I know fresh shrimp are quite delicious and probably great for them, are the ones at supermarkets and such fresh enough? <Yes> You know, the ones laid out on ice, that are already dead? <These are fine> Or will only the live ones, until the hour before you eat, okay? <Will learn to take bits of these> Can they OVEReat? <Can, but not common> He seems to bloat really easily while he's eating, and because I'm concerned with him overeating, I normally give the rest to our other fish. However, the few times he does get to try and eat a lot, he seems to stop himself. Do they always stop themselves before they explode =P, or should I be careful with feedings? <One should always be careful here> Since he's been with the same tank for a while now, but I suppose I should check in while I have the chance, right? He's about 7+ inches, in a 46gallon tank. A blue Gourami, a gold Gourami, a red-tailed shark, a Pleco, and 2 angelfish. The fish are all about 4-5 inches in length. He's not terrorized by any of them, never seen a mark on any of them, asides from the gouramis always having spats between themselves. Any problems with these? <Should be fine> The tank is well planted, with aged driftwood, a ton of leafy plants, an excellent&powerful filter, more plants, and err...more plants. =) No little tunnels for the Knifefish like I've read about having, but he seems to like the plants enough anyways. Should we find a suitable tunnel, anyways? <Mmm, not necessarily... I like transparent... glass "chimneys" or plastic... for viewing... but the plants are fine> Wow. Typing wayyyy too much now, sorry! ^^" For now, my mind has run out of pathetically inane questions to pester you with, so until later.... Thank you for all your help! <Thank you for writing, sharing. Bob Fenner>

FW algae and Apteronotus skin Hi, In my 29 gallon tank there are re-brownish specs on everything. My water parameters are fine and I do weekly water changes and cleaning. what do you think it is? <Almost undoubtedly algal colonies... take a read on WWM re> Also I have a Black Ghost Knife for about 10 months now and since November he has shown a weird green/brown gel-like coating over him. I thought it was Ick but wouldn't have died by now if that was the case. Do you know what it is and how to treat it? thanks. <This is probably the animals skin itself... and your good vision. The species is "quite slimy" in good health. Bob Fenner>

FW algae and Apteronotus skin, II Bob, than you for the response I just wanted to add that my knifefish's slime is a little whitish-gray when the aquarium light is on, does that make a difference? <Actually, yes... as stated, you have excellent vision, observation> I mean when I go to the pet shop all the ones are pure jet black. Jahner <These are more stressed... Bob Fenner>

Freshwater Question... Knife disease How long does it take for ich to kill fish? <Sometimes mere hours from the appearance of "spots", other times "never", the infestation existing as recycling generations...> I have a BG Knifefish and I thought it Had Gotten ich a couple of months after I got it. It has been 4 months that I see Some symptoms( green-like flour on him, yellow head stripe). When I got him his stripe was white I have raised the temp to 84, did many water changes and used medication at half strength. All water parameters are fine and the only other thing is that he is not that active from when I had him for the first 2 months( he is in a 30 gallon tank, about 5.5" long). His tank mates are a 3" Blue Gourami and a 4" Pictus cat (The cat showed symptoms but when I raised the temp. they disappeared). <They are VERY susceptible> I am Planning to move the 3 of them to a 55 gallon in the future (when should I get the 55 to move him into)? <Whenever you can afford it> What could this be ( Can you give me all the info you can)? <Perhaps "nothing" in the way of a biological disease... maybe another type of (internal) infestation... could be largely "untreatable"... If you have treated the system as you describe, I doubt if this is/was "ich"> Do BGK eat fish like angels, rams, Butterfly fish? Finally my friend wants to know, How many rams can you put in a 29 gallon tank? <This Knifefish does not consume any but the smallest of fishes... A twenty nine can house two pair of Microgeophagus. Bob Fenner> Jahner

Mainly Black Ghost Knife questions Hi and thank you WetWeb staff, My fish are doing great, after a very scary introduction. No one died and having been doing great (refer to suddenly stocked tank on WetWeb).  Well just a few questions, if I may.  But for reference I have a 55gal with Emperor 400, heater, etc., lots of (fake) plants, semi- fine (1/8" or smaller) substrate, a few rocks of different shapes making caves, heated to 80F, 7.8 PH, all levels great. a 8" BGK <Black Ghost Knife> a Pleco 6" 2- Blue Gourami (or Opaline Gourami not to sure because they have changed colors since I got the new one) a 4" and 2". a tiger barb 1.5" a clown loach 1.5"(just got him) a zebra loach 1.5" a ????? frog .75" I feed my fish a very wide variety of foods on a change by day basis.  My BGK has always been black and yellow I researched why because what I had seen was they should be white, I think on your site I was reading that some BGK are of a yellow variation. <Yes. this is so> Well my question is since I got mine a month and a half ago, he has started to turn whitish starting at the bands on his tail? I don't know why, I know that where he came from he was poorly fed and in a bad environment. Well Are there yellow variations or not (just mistreated BGK)? <The white/yellow markings do change with diet, water quality> My next question(s) is.  I now have 2 blue gouramis how long will it be before they will reach sexual maturity?, <A few months> I know they're bubble nest builders but have never seen them do this. I have lots of plants. is it a comfort level or something? <In part... also, the motion in the waters surface, the presence of other fishes> they seem to be very happy, the most aggressive feeders in my tank (other than the BGK at night). what I'm getting at is if they will\can breed? <Doubtful, unless given a calm, warm setting... on their own> I cant find anything on sexing them so I don't know. <Search the Net, books... not hard to discern if of size, maturity> and at the same time can my loaches possibly breed? <Can, but rare... they do get BIG (a foot or so)...> They are inseparable.  I would also like to get 1 or 2 Bala sharks (I am going to be getting a new 125gal in September and plan a move) will they get along with what is in my tank? What else is a possibility for moving fish? Thank you all for the site and personal help, James <Yes, and many choices. Bob Fenner>

Another Black Ghost Knife Question I Have a Black Ghost Knife 4", If I put on my Aquarium light (which I haven't turned on  since I had him, 4 months) will it stress him out or kill him well because they hate light and are nocturnal)? He does have this ornament with holes in it that he goes in and out of (prefers that then the ghost tube), can he be in there if the light is on? < Black ghost knife fish are nocturnal and should have a hiding place to retreat to when the aquarium light is on. They should be fed just after the lights are turned off.-Chuck> Thank You Jahner

Lifespan of a Ghost What is the life span for a typical Black Ghost? How sensitive are they to moving to a new tank? Nicole <Couldn't find anything on lifespan so I'm not really sure. They do like soft acidic water conditions. Move them the same as any other. Float him in the new tank in a bag of his current water. give it 20 minutes or so, then slowly pour in some water from the new tank. Do this a few times over an hour or so and he should be fine. If you test water check the pH of both new and old. If they are the same, you just need to match temp. Don>

Freshwater fish electro-sense question I recently bought an elephant fish. today my girlfriend surprised me with a black ghost knife. They are both about 3in and are in a 34 gallon tank with separate very good hiding spots. Will there 'electro-senses' clash? <There have been some studies on these electromagnetic fields generated by these fish but not much in the popular aquarium literature. But I am sure that they are aware of each other.> also how sensitive are they to salt? <These fish come from clean warm acidic water and have become very sensitive to salt.-Chuck> I use a little less then the recommended dose of aquarium salt(1tbsp per 5 gallon). tank also includes 6 glass cats and a blue lobster. thanks for your time. -Zac

New to Knives 8/2/04 I'm new on the knife fish thing so you might need to help me. I don't have any current problems but,  I want to know if three glass knifefish  in a 55 gallon tank is ok. < These fish have weak electronic organs and when they are kept together they seem to always be bickering  amongst themselves. They don't do any real harm to each other so if you have plenty of areas to hide then they  should get along fine.> Males grow about 18" and females 11". A fish manual says 1" per gallon that would be 54"  with three MALES. Here's the question. How do you tell male from female when they are the same size. < The books all say that the males get to be the larger fish. They are somewhat transparent so look for  differences in the body itself. You may not see any until they get close to adult.-Chuck> They are about 4".((I have other fish in there already.))  Please Help If Possible. Thanks.

Feeding a Black Ghost Hello, <Hi back! MikeD here>     I am a very new aquarium owner.<Welcome to the wonderful world of fish addiction, er, keeping.**grin**>  I am obviously still learning about everything.<50 years later, me too. The learning never stops>  I just found your site yesterday and I'm loving it!!  But I do have a question regarding a black ghost knife that I bought about 3 days ago.  I currently have a 60 gal. tank with 2 parrot fish, 2 black skirted tetras <In the future tetras and often barbs, do better in schools of 5-6 rather than in pairs> 2 catfish, 2 angel, 2 Gourami, and now I just added the BGK.  Is this too crowded??<Not necessarily. My biggest concern is did you give you tank enough time to cycle, and/or that you added all, or most of your fish at one time.>  I am feeding pellets and flakes to the other fish, and got some frozen bloodworms and shrimp pellets for the BGK.<This may work, but some ghosties can be a little demanding on food choices, especially when they are first obtained>  I feed them around noon everyday.  I understand the BGK is shy<Not shy, nocturnal, which are two separate things entirely>, but he will not come out of his hiding spot when I feed the tank.  My other fish not only eat all the flakes and pellets, they also eat the bloodworms and pellets.  I'm afraid they are not leaving anything for the BGK.  Do I need to change my feeding time or habits??<Yes, the Black Ghosts are nocturnal nighttime animals that often are very reluctant to come out into the open during the day. Usually, this will gradually wear off in time, but early on the best thing to do is feed it separate, just after turning off the lights at night. You might also want to keep check and make sure that it's eating what you are offering for food.  The bloodworms will almost certainly be eaten, while the pellets are a big if for now, possibly forever.  They also relish raw shrimp (either cut up pieces of human food shrimp or the small live ghost shrimp sold as feeders in many shops) live or sometimes freeze dried Tubifex worms, daphnia, etc.. Their absolute favorite food is live earth worms like you'd use for fishing!  Some will gradually start consuming "normal" aquarium fare while most others are always somewhat demanding and require special foods>   Thank you for your help and information!!<You're welcome and I hope this helps...the Ghosts are one of my all time favorite freshwater fish species> Mike

Black Ghost Knife Help Hi there from another fishaholic!<Hi Jennifer, MikeD here> Sorry to bother you with petty questions that really don't apply to any of your other visitors, but I *really* need some help regarding my black ghost knife.<One of my all time favorite FW fish> Although I generally research fish species very thoroughly before purchasing them, I only did a little such research before buying a black ghost knife. It was really pretty much an impulse buy, though I was at least somewhat familiar with the species.<They're pretty tough if handled right> At any rate, the manager of my LFS promised me that if I purchased one, he would do just fine in a twenty-gallon, provided he had plenty of coverage and was kept completely by himself. She did say that it was pushing the limits to keep him in a 20-gallon, but that he'd do okay, even as an adult. (He's 7 inches now.)<I'm not sure why they told you to keep it alone, as they do well with many other species if the tank is arranged correctly. As to the adult part, my largest grew to about 15" if that tells you anything> Now, I'm starting to have second thoughts on that. I assume he's okay for *now* in the 20-gallon, but will he really be okay when he grows up? I have an extra 35-gallon that I haven't stocked yet but it's very well planted and decorated, as I tend to pride myself on that. The problem is, it's very hard, brackish water, and it would be a huge inconvenience to redesign and refill the whole thing. Besides, I was really looking forward to the archers and Sailfin mollies I was going to keep... But, if I need to, I'm willing to change conditions if that's what it takes to save my ghost knife. (I simply can't afford another large aquarium for him.)<OK. While he WILL eventually outgrow the 20 (20L or 20H?), they are fairly slow growers so you've got at least a couple of years before it should become a concern.> Wow, you're very patient if you're still reading this.<Still here **grin**> I guess, to get to my point, can my ghost knife stay in that 20-gallon as an adult, or even now? Or will I have to completely revamp the 35-gallon for him? Would a 35-gallon even be enough? Should I just swallow my pride and give that poor fish to somebody that can take better care of him? Just how fast will he grow, anyway? Maybe slow enough that he could stay in the 20-gallon until I could afford a new tank?<I guess I should have waited until I got here to answer, eh? **grin**> Also, the LFS lady told me that black ghost knives can be held and are even intelligent enough to recognize their handlers... is this true? Sounds a little odd...<It depends on what she means by held. If you cup your fingers in the water, they will indeed swim into your hand if you train them.  I don't know what you're currently feeding it, but they also appreciate meaty foods, with their favorite being earthworms. They'll also appreciate ghost shrimp and even a piece of raw shrimp like you'd have for dinner, unbattered, of course.  These are small cousins of the electric eel, and I'm assuming you know that they navigate by true electronic sonar. Because of this, never add another S. American Knifefish or African Mormyrids, such as "baby whales" or "Elephantnoses"...they cross each others electric signals and a true war will result> Thank you SOOOOO much for your help! <You're very welcome>

Black Ghost Knife habits Good day, I am writing to ask about the black ghost's behavior. I notice that sometimes it lays on its side in the Mondo grass I have in my tank.  Is it 'sleeping'?  Or is it sick?  I have never had a black ghost until my brother bought one for my birthday the other day. any answers would be appreciated. < The black ghost is really a cool fish. Unfortunately it is nocturnal and is rarely seen during daylight hours. If you really want to see him out and about then you can turn off the aquarium light and feed the tank some black worms or live brine shrimp. Just use the room light to watch him. In bright light they will hide in logs or caves until dusk when they come out to feed. They get big, up to 18 inches but got to be up there as one of the strangest aquarium fish.-Chuck> Thank you! Eric

Black Ghost Knife Hi Bob, Nice site. Looks like you've got articles on everything in here. Hence I thought I might ask some advice. I've been keeping fish for a few years now and last year I took on a Black Ghost Knife fish as a favor for my local pet shop. I am aware of how long this fish will live and how large it will grow and I plan on getting a 60g tank in December. At the moment I keep her in a 20g tank with a few tetras and a beta but I have a spare (34g) tank that I've been using as a hospital tank for my marines. (I've added a pic of the big fella) Specifics are pH 6.8, Temp 25.4 'C. What I'd really like to do is swap the two round and have a good size tank to keep the BGK in. Thing is I can't really find out that much about them. I know it seems healthy, good color, eats well (even a couple of tetras once) and its very active at night. The fish has grown 1" in the last year (now 4") and now that I've given the rest of the community to my little sister (fast becoming an avid fishkeeper) I want to set up a species tank. Ideally I want at least one other BGK but sexing is impossible and I've read that they can be violent towards one another. Aside from these fish living in South America I know little else about their habitat. I was thinking of having a ground basalt strata with lots of spiral Val's and some floating plants to give better cover. Perhaps even some staged lighting to have a dawn dusk effect. If you give me a run down on the best kit to set up this king of tank what type of filtration, lighting, circulation and planting I'd be very grateful. Also should I go for a second juvenile and hope they grow up happily with one another, or is it better to stick to the one fish? < These are really cool fish. Unfortunately they are nocturnal and only come out at night or at dusk. They stay away from bright light. You might try red incandescent bulbs to observe them at night. They prefer clean soft acidic warm water and live food. They are prone to come down with ich and are difficult to treat. This could be because they are rarely seen by aquarists and  are often diagnosed too late. They like lots of shelter during the day so caves and logs are appreciated. Years ago they made " Black Ghost Houses" which were nothing more than clear plastic tubes with little feet on them. This way the ghost thought it was hiding. I don't know how well they worked or if they still available any more. These fish really don't see that well and get around by using a week electrical field like electric eels to get around. They get up to 18 inches and are being bred in Thailand.-Chuck> Kindest Regards, Carraig Tuomas

Black ghost Knifefish  hi, I need some advice concerning my ghost Knifefish, I've got a 5ftx3ftx2ft tank(400 litres) I have 1 rather large goby an Arowana 2 angels and 1 Geophagus brasiliensis a few Kuhli loaches and a bristle nosed Plec, lol of which seem to get on fine. last week I fell in love with a ghost Knifefish but since he's been in the tank I've hardly seen him, or seen him eat anything. the goby that I've got is very greedy and I'm worried if the Knifefish getting any food, what should I do???? any advice would be greatly appreciated, thanks Julie < Your knife fish is nocturnal and will only come out a night. If you put on a red light bulb at night you will see him out an about. To make sure he is eating I would turn out the lights and then feed the tank. They can be very picky and sometimes only eat live food. I would place some live black worms in the tank after I turn out he light at least once a week. If you ever got an elephant nose then I would recommend the same thing. -Chuck> 

Need Help I am at a complete loss, and I'm now turning to online resources in my desperate attempt to find a solution to my problem. I found your site to be very impressive; very rarely does one find a resource that contains such a wealth of valid information. I work at a large chain pet store, in the aquatics department. All of us in the department are extremely knowledgeable about fish and their care, and rarely have any problems with any of our fish. However, whenever we receive a shipment of black ghost knives or clown knives, the fish systematically die off within a couple of days. We have no problem with our brown knives, ever. We keep each species in their own tank, the brown knives in a larger tank with zebra Danios (they never come in large enough to eat the Danios), and the ghost and clown knives in their own smaller isolated tanks. We offer ample hiding spots for each type of fish. We feed each frozen food, such as bloodworms, nightly. Our pH is a little high, around 7.8, and our water hardness is through the roof, but our temperature is a consistent 78 F. We always carry juvenile fish; the knives never come in larger than 4 inches or so. We would like to carry ghost and clown knives, but not if it means continuous losses such as we have experienced. If you have any advice as to what we might be doing wrong, and what we might to do rectify this, it would be greatly appreciated. My thanks in advance. L Barker  <<Hello. I need to know if you guys are putting these fish into properly cycled tanks. I know it sounds simplistic, but it would make me feel better if you could provide me with information on ammonia levels, nitrite and nitrate levels in these tanks. The problem with being a store is that as the fish are gradually being sold, over time, the beneficial bacteria can die off without us being aware of it...then along comes a new shipment, and twenty fish are suddenly put back into tanks with limited bacteria. The ammonia level can skyrocket the first few days, resulting in sick knife fish that never fully recuperate due to all the stress from shipping combined with new surroundings...and undoubtedly bad nutrition before you received them. Also, smaller knives are even more sensitive than larger ones. You may have a better survival rate if you can specify 3 inches or LARGER when you order your knife fish. Try, and see. In the meantime, prepare your knife fish tanks either by keeping them full of other species at all times to keep the biofilter alive, or by using pure ammonia to keep the nitrifying bacteria alive, until the shipment lands. You can also try running some peat moss to help lower pH and hardness levels, though these, in and of themselves, should not be enough to kill all the newcomers alone, but it doesn't help when added to the other stressors the fish are facing. Also, keep in mind that knife fish are aggressive amongst each other, and make sure to provide plenty of PVC tubes for the ghosts, at least one per fish!! Keep the lighting low for the first few days, as well. You can cover the tanks with Styrofoam lids to diffuse the lighting, or leave the lights off entirely. -Gwen>>

Ghost Knife Changing Colors What causes a black ghost knife to start to lose its color and turn a silvery white? <The first thing I would do is test my water, poor water quality, stress, age, diet, there are many things that can attribute to these fish changing color.  Gage> 

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