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| FAQs on
Black Ghost Knifefish,
Apteronotus (Sternarchus) albifrons, Systems
Related Articles: New World Knifefishes, Gymnarchus, Notopterids/Clown Knifefishes, Electrogenic
Fishes,
Related FAQs: Knifefish Systems,
BGK FAQs 1,
BGK FAQs 2, &
FAQs on: BGK ID, BGK
Behavior, BGK Compatibility,
BGK Selection, BGK Feeding,
BGK Disease, BGK
Reproduction, & Knifefishes
1, Knifefishes
2, Knifefish Identification,
Knifefish Behavior,
Knifefish Compatibility,
Knifefish Selection,
Knifefish Feeding,
Knifefish Disease,
Knifefish Reproduction,
Electrogenic
Fishes, Notopterid Knifefishes
(Clowns...),
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Ghost knife, BGK beh., sys.
3/3/08
I have had a 40 gallon freshwater aquarium for several years, and until
recently the tank was home to a few Oscars who eventually out grew the tank and
now reside in a friend's outdoor Koi pond. This past Christmas 12/07 we decided
to re-establish the tank with two silver dollars and one incredibly elusive
ghost knife. The tank contains your basic under gravel filter, bio wheel, plenty
of colorful plastic plants and a long plastic tube, guess who lives in the tube.
When I purchased the ghost knife from the pet store he was in a tank with
several other ghost knifes and no real shelter, he was swimming around the tank,
front wards, backwards and performing all sorts of tricks. Now that the ghost
knife has a place to hide he never comes out of his tube. I love to tell friends
about this mysterious looking fish, however when they ask to see him I can only
reply with ummm sorry he's still hiding. Any suggestions on how my ghost knife
can overcome his shyness?
<Apteronotus is only active in dark, shady aquaria. You need a soft substrate
for digging, lots of rocks, and real or plastic plants that reach up to the
surface of the aquarium and produce lots of shade. Use LOTS of floating plants
(Indian Fern is ideal). What you do not want is brightly coloured gravel,
bizarrely coloured plants, or bright light. Sounds and vibrations must be
minimised, so don't put the tank near slamming doors or loud TV sets. Bob F just
wrote a piece on setting up an African-themed aquarium, and the photo of the
tank shown there is precisely what you need for Apteronotus, so have a read:
http://www.wetwebmedia.com/FWSubWebIndex/fwlvstksel.htm
Apteronotus live in major river systems and expect excellent water quality and
lots of water movement. I'd be aiming for NOT LESS than 6 times the volume of
the tank in turnover per hour. These are NOT easy fish to keep, and when kept
poorly become shy, and often die.>
I also wanted to know if adding aquarium salt when doing water changes was
harmful to the ghost knife?
<Yes.>
I know with other fish that I have had, I have added approximately 1 teaspoon of
aquarium salt for every 10 gallons, however I recently read that ghost knifes
are not particularly found of chemicals such as prime coat and aquarium salt.
<Indeed. The addition of Prime Coat and aquarium salt is unnecessary in a
properly run aquarium. Instead focus on filtration and water quality. 50% weekly
water changes and nitrates below 20 mg/l, and of course zero ammonia and
nitrite, are what you are aiming for. Cheers, Neale.>
Black ghost knife attacked by
loaches 1/14/08
We purchased a black ghost knife 3days ago and from the very beginning the
fish swam near the surface on it's side and it seldom ventured to other parts of
the tank. The fish was approximately 4cm in length. In our tank we also have 2
clown loaches, 2 Pakistanian loaches, 1 Corydoras, 1 angelfish, 3 gouramis and a
small eel.
<One Corydoras isn't nice. Corydoras are SCHOOLING fish, which means they should
be kept in groups. Please add some more of the same species (unless you want to
accrue a lot of bad Karma from the catfish gods).>
We started noticing that the black ghost knife was being attacked by the
loaches. The clown loaches are approx 6cm and Pakistanian loaches 4cm.
The tank is 4feet in length (980 Aqua One) The tank has 2 plants and water is
changed regularly, 25% biweekly. There is a large rock with many holes to swim
through and places to hide as well as a fake pot with hiding capability. The
temp of the tank is approx 28degrees C. The tank was 34degrees C when the fish
was first put in; our thermometer was not working but I realised the temp when I
stuck my hand in. I slowly reduced the temperature using ice blocks. The pH of
the tank is approx 7.2
The bottom feeders are fed the appropriate pellets once a day and we were
feeding the others blood worms. The only other thing I have noticed in the tank
is a yellow (algae?) growing on the sides of the tanks in round circles similar
to what would be seen with bacterial growth. We put in anti-algae drops and
cleaned the tank to deal with this. I have not yet observed any re-growth.
<Don't use Anti-Algae medications; they cause major problems, not least of all
their toxicity to other organisms as well as producing nitrate spikes as all the
algae die. What you have sounds like Diatoms, a type of algae that grows most
noticeably in aquaria that are not adequately illuminated. Easily beaten by
installing strong lights and lots of fast-growing plants. Nothing else works,
other than manual scraping.>
1. do you think the ghost knife was unhealthy from the beginning judging
from it's behaviour?
<It was probably fine. But Apteronotus albifrons is NOT an easy fish, and is
extremely sensitive to poor water quality as well as medications/potions of
various types.>
2. is it normal for loaches to attack black ghost knives?
<Loaches are, with a few exceptions, NOT NICE FISH. They aren't community fish
(exceptions are Kuhli loaches, Weather loaches, and to a certain degree Clown
loaches; everything else is more or less aggressive and should be treated as
such).>
3. We would love to get another black ghost knife but not if it is doomed to die
before it's time, can you suggest any other reasons for the loss of our fish and
tips to keep one safe in future?
<Hmm... not impossible to keep, and under good conditions live many (10+) years
in captivity. But you do need to cover all the bases... these aren't like Danios
you can just add to a tank and hope for the best. They have very specific needs
in terms of food, hiding places, substrate, etc. Do read here:
http://www.wetwebmedia.com/FWSubWebIndex/bgksys.htm
If you need more info, get back in touch!>
Thank you for your time.
Sincerely,
Ali.
<We're happy to help. Good luck, Neale.>
BGK... sys.
01/13/2008
hi there, I have a quick question. What is the minimum tank size for a black
ghost knife fish? Also are they freshwater or brackish? Thanks.
<... a small individual Apteronotus... 29 gallons... a full-size one... at least
55... Strictly FW... RMF>
Re: parrot fish with mymorus
tapirus (freshwater African dolphin)... Now BGK sys. 1/9/08
p.s. after doing some more research, I fear that my 55 gallon will
eventually be too small for the black ghost fish. is this true?
<Eventually, yes. Maximum size in the wild is 75 cm, though aquarium specimens
are generally smaller, around the 50 cm mark. While this takes many years to
reach, this is ultimately a better fish for the 75-100 gallon tank than the 55
gallon tank. So does depend on where you see yourself five years from now in
terms of aquaria.>
if so, he's going back to the store as well....
<Hmm... does underline the need to research the fish *first*, then spend the
money. Cheers, Neale.>
Was: BGK/Cycling a Tank/Dyed
Fish 8/2/07
Thank you so much for such a speedy response, it means so much. To answer
your questions; The tank I have him in is only a 10 (I know he will grow out of
this very quickly but he'll only be in it a couple more days.) I figured this
was okay as when I got him he was no more than an inch big. He shares the tank
with two "painted" tetras that got put in there a day after I set the tank up.
They did fine, so I a day later I put the BGK in. Unfortunately, I was told 24
hours was all it took to cycle a tank [And I work at a fish store ;\ ] After
setting up the tank and reading some information on your website, I realize I
should've let it run for at least 2 weeks.
<Please read much more on cycling tanks. You could let a tank run empty for a
year & it wouldn't cycle. Find out more about the bacteria needed to break down
ammonia to nitrites, then to nitrates, which much be removed by weekly water
changes. This entire process can take 2 weeks, if "fishless cycling" & up to 6
weeks if cycling with fish (bad idea--stressful to the fish). All this info is
on our site. For an instant cycle you can use Bio-Spira. I recommend you use
this to cycle your larger tank immediately. You owe this to your customers to
know all this.
Please urge your manager/owner not to carry dyed fish!
See: http://www.deathbydyeing.org/ (can't seem to get that site to work but
excellent info there),
http://en.wikipedia.org/wiki/Painted_fish
http://www.practicalfishkeeping.co.uk/pfk/pages/campaign.php
Just do a search on "dyed fish" & you'll find countless arguments against it. I
will not buy from any store that carries them.>
But I have kept that in mind as the BGK's new home, a 29 gallon [and not
permanent] home is being cycled as we speak.
<Check into the adult size of your fish. You will eventually need a minimum of a
90g tank. You owe it to your customers (& the fish) to know the adult sizes of
all the fish you sell & the minimum tank size for an adult. You are aware this
fish won't eat flake food? My 15" fellow only eats live blackworms.>
Anyway, as soon as I got your e-mail I ran out and got both the Melafix and
aquarium salt. So I'm hoping by tomorrow, he will clear up a bit. Again, thank
you for your helpful response, and your time, I appreciate it very much.
<I suggest daily 50-80% water changes, until you can upgrade him to a cycled
tank. ~PP>
-Adam
Black Ghost Knife, yellow water, killing fishes
I have a couple questions for you, I hope you take time in answering mine. I
see you do take a lot of care in the questions people ask. Here's one; I am wanting to buy a black ghost knife
fish. Is this fish territorial? I already have a loach in here and I don't want them to
fight.
<Likely will get along>
Plus we don't want to buy pellets or freeze dried food, so will it survive on flakes?
<No>
My loach has been surviving for a couple months without those foods.
<Won't be healthy on nothing but flakes forever>
My second question is, my tank is getting yellowish color really fast and we clean our tank
(55 gallon) like once every 2 months. What is up with that?
<Need to do more frequent, partial water changes, maybe weekly... and possibly use carbon in your filter flow path>
My final question is, my fish seem to be swelling up really badly, and then just die.
I put in some medicine. Is this what you call ich, if so what is it and how do
I stop it? Thank you.
<... time to study... and adapt a better maintenance schedule... It sounds like your system needs more regular care... likely your fish deaths are due to poor husbandry, a lack of nutrition, perhaps mis-medicating. Take a read over our website:
http://www.wetwebmedia.com/FWSubWebIndex/fwsubwebindex.htm
re Set-Up, Knifefishes, Maintenance... IF you want to be successful at keeping an aquarium you need to learn more re what it takes to care for it. Bob Fenner>
Black Ghost Knife
I read that a BGK likes tank temp.s up to 82 degrees. I've raised the temp. to
help cure him of a series of illnesses and he's been in an 84-85 degree tank for about a month and a half now. How long can he tolerate the higher
temperatures?
<Indefinitely actually... will shorten lifespan a bit... but the only real worry here is aeration... dissolved oxygen is less soluble and metabolic rates elevated at higher temperatures...>
I'm still treating him (with Paradigm for flukes, worms etc) so I wasn't planning on dropping the temp until this one hopefully goes away.
Thanks so much for all your great info - you've been a really wonderful resource.
<Glad to help. Bob Fenner>
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>
Ghost knife fish
Hi,
I'm totally new to keeping fish ..... Recently, (about 2 days ago) I
bought 2 knife ghost fish and a new fish tank for them .... I did not
do research before buying them. So here's the problem ... the new tank
is totally empty .. I haven't had time to go get those "hiding" places
for them .... Only place they hide is behind a pump in the tank and
they seems to be fighting for the space ..... Do I have to separate
them using a partition in the tank ? Also one of the them had the fin
like "broken" that like hair .. not in one whole piece as like the
other... is there any wrong with it ? and what should I do ?,
< Black ghost knife fish are nocturnal (feed at night), so they don't thrive in
brightly lighted aquariums without suitable places for them to hide during the
day. You really don't have to separate them as long as you give each of them
their own shelter to go to during the times you have the lights on. Get a
couple pieces of PVC pipe from the local hardware store and throw it in there
for now and they will be fine . Although the tank will not look to good with a
couple pieces of white pipe in it.-Chuck>
Thanks a lot
Chasel
Re: Attempt to save Ghost knife fish
Hi,
Thanks for the last reply. However, I'm sending this out in
attempt to save my fish. I now have a tank with some plant and a log
inside, 2 black ghost knife fish and a swordtail. They live fine with
each other and I had been feeding them with flask and they ate them.
< Sorry . don't know what flask is so I don't know the significance is if the
black ghost knives ate them>
But just yesterday, I notice my 2 black ghost fish are not doing well.
They aren't moving much even when I turn the light off ....and not
feeding either. I have no idea why this is happening. I don't have any
tester to test the water condition. My last water change of 30% was
5 days also. They were still fine then. I don't know what else I can do. All
I did was a 30% water change this morning hope to save them. Any
similar situation to help ?
< Well I guess we need to determine if their behaviour change is a symptom of
something more serious. Try feeding some California blackworms, often called
Tubifex still at some pet shops across the U.S. If they don't go for this look
carefully for signs and symptoms of some things we can specifically treat. I
really don't like to medicate a tank if it is not needed. In the meantime make
sure that the water is up about 80 degrees F and the filters have been serviced
and do another 30% water change. This should take care of any water quality
problems. If the fish don't respond then I would remove them to a hospital tank
were they can be observed more closely and look for symptoms.-Chuck>
Thanks
Chasel
Re: Attempt to save Ghost knife fish, II
Hi,
Its was a typo on the food I feed them. I meant flake. But
anyway, one of them is dead and the other one is laying on the floor
now. I did another 30% water change, no use. I move the last one to
another tank with and 80% fresh water no use either.
Thanks anyway
< Black ghosts like warm acidic water and usually don't eat flake food. If the
water they were kept in was hard and alkaline then their kidneys may have failed
due to an imbalance of minerals in their system. Hard to tell. Sorry about your
fish.-Chuck>
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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>
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
Ghost knife?
Hi there guys,<Hi Guru, MacL here with you.> Absolutely love your web site..
I was wondering if you knew what size tank I would need to get my ghost knife to
grow to its full length, and also roughly how big it would get in a 900L tank
(approx 240 U.S. gallons and 200 UK gallons). <Guru I need a little bit of
clarification. Do you mean a black ghost or one of the other types of knife or
bony fishes? If you take a look here you might find your answer, otherwise if
you can clarify for me a bit we can go from there.
http://www.wetwebmedia.com/FWSubWebIndex/knifefishes.htm>
Regards
Guru
Black Ghost Knifes
Hello. I read the FAQ but I am unable to find the answer for my question. I
have a rectangular tank is 16" x 9" x 11". But I have 2 ghost
fishes. It is healthy for the fishes? I noticed that they sort of
dance/swerve/bite each other in that sequence. I am afraid that they are trying
to kill the other off. I bought a volcano rock (that's what the shop says) for
the fishes to hide. Seemed like they don't share. Should I buy another one to
keep the other happy? 1 last thing, the fishes don't eat the flakes floating on
the water. Instead they scoop around the top edges of the tank.
Thanks. I really those answer. Please
<These fish need a larger tank, at least 55 gallons even that may not be big
enough to house 2 of them, they are aggressive towards their own kind. Check
out the link below for more information on these fish. Best Regards,
Gage
http://www.mongabay.com/fish/knifefish.htm >
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 Betta 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 Fish
Hi
<Hello>
I am setting up a tank for a ghost fish and want to know what
sort of plants are good for putting in the tank and what other fish are suitable
if any
<Tropical South American plants are my fave... ones that would, could be
found in the same habitat. Tropica has a nice website that shows some of these
biotopes... and maybe some sunken driftwood. Many medium sized characoids
(tetra) fishes will go with this Apteronotus... as well as Callichthyid
catfishes... even angels. Bob Fenner>
Cheers Shelley Molloy
Black ghost knife problems?
Hi Robert,
I'm a bit worried about my new BGK (my new favourite fish!). I am currently setting up a new tank after becoming addicted to my boyfriend's set up! New
tank is 80 litres, planted and has a fine gravel substrate. It is currently stocked with 2 Pearl Gourami, 2 Angels, 3 Tiger Danios, 2
Corydoras sterbai and a small (2.5 inch) BGK.
<This IS small!>
Tank is two weeks into its first cycle.
<Yikes... Knifefishes don't "like" new systems... Hard on them to go through their initial chemical, biological changes>
The BGK has been in for 3 days and while it seemed happy in the first two (hiding amongst plants) but I have
come home from work today and it doesn't seem right. It is sort of hovering around the bottom of the tank, moving around almost like a drunk person. It
kind of wobbles around a bit, then rests and then wobbles around again. It has plants to hide in, as mentioned, and also a piece of driftwood to go
under but it doesn't seem interested in this.
<Mmm, well, this is pretty standard behavior for the species... but... do you have another, older system you can/could move it to?>
At the LFS it was happy hiding amongst Java Moss and seemed unconcerned with the lit tank
(I'd watched it there for a couple of days and it seemed very strong and healthy).
There are really no other signs/symptoms except this apparent listlessness and my gut instinct (and it appears to be easily caught in the relatively
light current and moved along which wasn't happening yesterday). I checked the water parameters and everything was fine - Ph 7.0, temp 26C.
Nitrite was very slightly elevated but not of note (I have added Amtrite down to fix this.)
<Mmm, only temporarily and at a "cost"... as stated, Apteronotus don't like "going" through cycles>
Is it just acclimatizing or do I have a problem??
<Perhaps both>
Please help, I was really impressed with what I've seen on the site and decided you're the man to ask!
Thanks.
Alia
<Best to move the specimen to an established, similarly peaceful setting, second best to be very careful of not feeding much, urging your completion of biological filtration (Please see here:
http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm.
Bob Fenner>
Black Ghost Knife / Filter
Contamination 9/4/07
I'm an intermediate fish keeper, have been doing it for a few years
(beginner still, I suppose). Started with 5 gallon, then 20, and now a 72 bow.
It has a wet/dry filter a temperature of about 81 degrees, and as far as water
quality, I haven't read ammonia, nitrite, OR nitrate in the past 6 months, and a
PH hovering between 7.8 - 8.0. It's fairly established, maybe 9 months old,
tropical community.
<All sounds very promising.>
I recently purchased 2 Black Ghost Knives (BGK) fish from my LFS, and added them
to tank (yes, I know quarantine should be done, but college has me on a
nickel-dime style budget).
<Ah yes, I remember those college days well!>
The fish (perhaps 4 inches) seemed very content, swam happily, found hiding
amongst rocks and water lilies, and came out at night to feed. None of the other
fish were aggressive towards the knife (with possible exception of Zebra Danios,
but they stay topside, and vice-versa for BGK).
<OK.>
After two days, I had the lovely sight of coming home to one of my BGK's stuck
to the strainer on the overflow... lived through that, but died soon thereafter
(my fault, water flow rate has been adjusted accordingly, they won't get stuck
now).
<This doesn't sound like cause and effect to me. Apteronotus live in big river
systems, in quite deep water. It seems unlikely to me that a filter could create
too much current for this sort of fish. Usually, when someone finds a fish stuck
in the filter, the fish died, or was weakened, and the filter merely dragged the
body towards itself. A healthy fish should have no problem avoiding a filter.>
That death I can understand.
<I can't.>
Five days later, I wake up to see my other BGK lying on the sand (dead, of
course).
<I see. Now this sounds as if you have two cases of Apteronotus death, with the
filter implicated just the once. This reinforces my opinion that the filter had
nothing to do with death #1.>
No visible signs of biting or otherwise aggression related harm. I'm totally
stumped. My question to you is this: Could the slightly high pH of my tank have
slowly killed him, or could it have been something else? I'd like to get
another, but I want to be sure of the problem on my end (if there is one) so I
can fix it, thus avoiding an unnecessary death of a beautiful fish.
<Apteronotus are not easy fish. They are incredibly sensitive to water quality.
In terms of water chemistry, they aren't especially fussy (Fishbase reports pH
from 6-8, 5-19 dH) and comparable to most other South American tropical fish. So
your pH/hardness issue is unlikely to be the cause of death. The exception here
would be if the water chemistry *varies* a lot. But provided it was constant,
even a relatively high pH shouldn't be a problem. (This is true for most
freshwater fish in fact: steady water chemistry is more important than clumsily
going after some mythical "optimal" values.) So, here's what I'd be
investigating. Firstly, is your water chemistry very different to that in the
store? For example, do you soften or acidify the water, or add peat to the
filter. Secondly, what scale/frequency of water changes do you do? Weekly 50%
water changes should prevent the inevitable background pH change in all aquaria
from becoming significant. But if you do small water changes, say, 20% every
couple of weeks, then the pH could drop in the aquarium over the two weeks, and
then rapidly go up when you add new water. This would be bad. Thirdly, I'd be
testing for nitrite across the day, maybe three or four times. Sometimes, tanks
develop nitrite problems shortly after feeding, but seem to have zero nitrites
at other times. Spikes in nitrite concentration would be lethal to something as
sensitive as Apteronotus. Fourthly, are you adding anything to the water (other
than dechlorinator, naturally)? Some benighted folks go round adding stuff like
salt and anti-stress medications on a weekly basis, and while hardy tropical
fish shake off these misguided annoyances, Apteronotus will not. While we're on
the topic of dechlorinator, make sure yours removes chloramine, if you live in
an area where chloramine is used. Finally, did you add any medication?
Apteronotus are intolerant of many commercial brands of things like
anti-whitespot medication. If you used these in the recent past, adding some
carbon to the filter for a few weeks might be a good idea.>
Any help is greatly appreciated!
<Done my best!>
-Brandon
<Cheers, Neale>
(thought of another question, couldn't get a straight answer elsewhere)
<OK.>
In my 72 gallon tank w/ overflow and wet/dry filter, I use a filter pad that
claims to be re-usable with cleaning. It's instructions for cleaning are to soak
1 part bleach w/ 10 parts water overnight, then rinse, then soak in plain water
overnight again. Is this adequate to rid the bleach? I've had some strange
occurrences lately (mollies dying, no reason) given my water quality is good (0,
0, 0, pH 7.8 - 8.0, 81 deg.), and am starting to think it might be bleach
contamination. Just curious on any insight or special tricks to know when the
bleach is chemically gone, not just sensibly. Thanks!
-Brandon
<Agreed, this sounds like a dumb idea, so not sure why the manufacturer are
recommending it. If you need to wash something, hot water should work fine.
Sometimes I soak things in brine if these need a deep clean (e.g., it's an
ornament I left out in yard over winter and its covered in mud and slime). Once
you rinse the thing off, any traces of salt will be harmless. It is entirely
possible traces of bleach have irritated your fish, leading to death. So, stop
doing this. Clean the filter the old fashioned way (in buckets of aquarium
water) and then replace sponges when they are so clogged they can't be cleaned
any more. NM>
Re: Black Ghost Knife /
Filter Contamination 9/5/07
Thanks for all the info on the BGK!
<You're welcome.>
I do bi-weekly changes of about 20%, so I would assume from your reply I should
be doing something more towards 40% on a weekly basis?
<More like 50% for something as sensitive (and big) as Knifefish.>
(Sounds like a lot of water, closing in on 30 gallons).
<Them's are the breaks.>
I use a product called "Prime" to treat incoming water, as well as some time
(chlorine has a slight evaporative property if I recall correctly).
<Absolutely DO NOT rely on chlorine evaporating. Use the full dose as stated on
the carton, and stir well. Also, if your local water board uses chloramine, that
won't evaporate.>
I will begin more thorough logging of pH and nitrite for a two month period or
so,
to see average variance.
<Very good.>
In summary, I suppose, a 30-40 (even 50) % water change weekly would maintain a
stable pH for my tank, and not be detrimental to the fish at the same time (in
terms of massive quantities of water coming in and out on a regular basis)?
<Assuming you do the water changes regularly, the dilution effect will mean the
pH/hardness in the aquarium will be approximately equal to your tap water
supply. A week isn't long enough for the pH to drop much. The main thing is to
check temperature of the new water matches the old, so that there isn't a huge
temperature drop when you add the new water.>
It probably was the pH, because now that I
think about it, I changed 13 gallons of water the day before he died...
<Sounds like clutching at straws. What makes you think the pH changed? What's
the pH of the tap water, and what's the pH in the aquarium? Water changes where
the pH/hardness are the same in the old water and new water DON'T DO HARM.
That's old school fishkeeping. Nowadays we've learned new water is best, and
some people even do 90% changes per day!>
I'm so sorry for all of the questions, but I care for my fish more than most
people, and I want to do everything I can to ensure their good health.
<Very good.>
In regards to the filter pads, the problem with just washing with aquarium water
is that it won't clean it well enough.
<Get over it. Biological filter pads don't need to be deep cleaned. All you need
is to rinse off the worst of the silt. So, don't EVER wash biological filter
pads in anything other than aquarium water. For the mechanical filter pads, deep
clean with hot water, or else replace with new ones. Now, this said, if your
filter is getting so dirty the pads are irretrievable, then you are either
cleaning the filter too rarely OR you have too small a filter for your aquarium.
Under normal, correct use a filter should only need cleaning at most once a
month, and even then the sponges should be easy to clean in buckets of water.>
I set mine up as two-stage filtering, first is a large plastic pad (kind of like
a scouring pad) to catch large debris (and the occasional small fish).
<????>
The second one (which is bleach cleaned) is a 100 micron pad, looking more or
less like felt. This makes for remarkably clear water, but the downfall is that
they needeth be changed every three days at best.
<The second filter is the biological filter. You absolutely should not be
cleaning this in anything other than aquarium water. Your filter sounds
basically inadequate, and almost certainly not removing nitrogenous waste
quickly enough. And that's why your Apteronotus died. Until you create and
mature a more reliable filter system, don't buy any more fish>
At $20 for every 9 of these, it can add up. Bleach cleans them wonderfully, but
I suppose if it's hurting my fish I shall find another way.
<Indeed you MUST. Please read the articles here at WWM on filtration. I'm not
convinced you understand the theory and practise yet. You shouldn't need to
replace filter media more than once a year, and I don't replace biological media
for periods of 5+ years at a time. If you're finding your filter media
completely clogged up and useless before then, you have a problem.>
I much appreciate your help, and in a few weeks, maybe a month, I'll take
another shot at a BGK, and I will be sure to let you know of the happenings of
him/her).
<No! It will take 6 weeks, minimum to mature a biological filter to the point
where it is stable. Since Apteronotus don't do well in "new" aquaria, I'd not
expect to keep one safely for at least another month or two after that. You need
to review your filtering system. Minimum, it should provide 6 times the volume
of the tank in turnover per hour (i.e., for a 55 gallon tank, the filter should
be rated at around 330 gallons per hour). The filter media should stay so clean
that you only need to rinse them off every 1-2 months. If you don't have these
things, you don't have a system that can contain Apteronotus albifrons. Buy
another one... and it'll die.>
-Brandon
<Good luck, Neale>
Re: Black Ghost Knife / Filter
Contamination – 09/05/07
Again, thank you in kind for the help!
<You're welcome.>
My tap water has a pH of about 8.0.
<Admittedly not ideal for this species. But not toxic, either.>
Prime removes chorine and chloramine. I mix water with powerhead in large plastic
tub with its own heater and digital thermometer to make sure it's within 0.2
degrees of tank. I can deal with lots of water usage, lives are at stake here
;-).
<It's not so much that, as the fact doing a 50% water change compared with a 20%
one really isn't that much work by the time you have the buckets and hose pipes.
So you may as well do a big water change and improve water quality while
inhibiting background chemistry changes.>
Best thought about pH being cause of death (more likely TDS or dH) is that I had
gotten behind on water changes (school starting, personal issues, etc..) had
been maybe a month. I can imagine pH could have dropped enough to cause a shock
to a Knife when higher pH water was added.
<Indeed. That's why we need pH test kits.>
The filter pad in question is not the bio-filter. It's a mechanical pre-filter
for a 75 gallon wet dry filter with a 700gph pump (which probably puts out more
like 500 with head and friction loss) = ~ 6-7 times turn over rate in tank (on
full flow - have a diverter to pump part of flow right back in sump if flow need
be slowed down - doesn't restrict flow from pump, but does to tank). Will
probably switch back to a more conventional pre-filter (i.e. floss pads or
similar) to alleviate consistent changing of micron pad (which was every 3
days). These are easily replaced, so no need to clean, right? Biggest thing that
clogs micron pad is plant matter (tank is planted, and a Geophagus brasiliensis
enjoys digging them up/ chewing off bits of plants). Tank is established (in my
mind, at least) being almost a year old with no traces of ammonia, nitrite, or
nitrate in the past 6 months. The bio-balls never clog, but the mechanical
pre-filters do in time, from said plant debris. I think
you simply misunderstood my filter type, perhaps thinking I had a large
power filter or something similar. The wet/dry is marvelously efficient for
freshwater from my experience.
<Agreed, these filters can be very good. If the pre-filter is clogging, then
just use something cheap instead of the expensive units supplied with the
filter. Ordinary filter wool should work, no? Alternatively, clean the
pre-filters much more often, every couple of days if required, just rinsing them
under the tap.>
I also enjoy very much reading your site, I spend a good hour a day, 5 days a
week on here trying to learn more.
<Glad you enjoy.>
Anyways, I will try the larger volume water changes and see how it works
with current fish, and continue to test pH (and possibly carbonate hardness and
TDS...read up on those, apparently too many TDS can cause a difficulty for
fish's cells absorbing the diffused oxygen in the water, and as for the hardness
(if I read correctly) if the hardness is maintained, the pH will be less likely
to change, hence providing a more stable water chemistry, which is the overall
goal here).
<In theory, yes, TDS (total dissolved solids) is related to osmoregulation. BUT,
once a fish is acclimated to a certain TDS level, sudden changes, even towards
"better" levels, can be bad. So it's better to have a fish acclimated to the
"wrong" water chemistry but maintaining very stable water chemistry and quality,
than trying to force your tank to the "right" water chemistry while bouncing
around pH/hardness in the process and skimping on water changes because of the
expense. In other words, don't fixate on the value so much as the stability and
quality.>
I am greatly in debt to your help, and am hoping to learn how to maintain a VERY
stable water condition, because I am very bent on being a successful BGK keeper
(saw a nice 75 gallon tank the other day, would make nice home for a few years
for him... till he got bigger, that is).
<There's no secret to stable water conditions: big tank, under-stocking, good
filtration, and above all, large and regular water changes. Likewise, the causes
of unstable conditions are well known: too many fish, lots of organic decay
(plants, general muck), clumsy manipulation of water chemistry through use of
peat or buffers, and infrequent water changes. So, do the first list of things
and avoid the second list, and you're laughing.>
Hopefully I can apply everything I've learned from you and this website to make
it happen. Thank you more time!
-Brandon
<Glad we could help. Good luck, Neale>
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