High nitrate levels in pond and aquarium
4/18/20
Hi Bob and Friends,
<Hello Annette.>
Recently my platys have been dying. All my other
fish seem ok. I did a water test kit from API and the pH was 7.6,
but the nitrates were at 160 ppm, which was the
highest level.
<Yikes! That'd be the reason. Fish vary in response to nitrate.
Cichlids and Mollies are very sensitive, and long-term, anything
above 20 mg/l can cause health problems. Most community fish will be
fine up to 40-50 mg/l, and characins and catfish seem to be, on the
average, among the least sensitive fish (which probably explains why
they were old favourites for community tanks up to the 1970s, when
people avoided water changes).
Platies are likely to be more like Mollies, so your high nitrates
could easily be the problem.>
Is there anything I can do?
<First up, a water change. Do a series of changes across the next
few days, such that you change 30-50% of the water each time. Try
and keep water chemistry and temperature steady. After a few days,
nitrate should be close to whatever your tap water level happens to
be. Secondly, review stocking, tank size, and feeding. The old rule
that says "an inch of fish per gallon" is pretty good, so if you
had, say, 10 platies, these are about 1.5-2 inches long, so you'd
need 15-20 gallons to keep them. Any additional fish would be added
to that, so if you had, say, six Corydoras catfish, each about the
same size, they'd be another 9-12 gallons, so together your tank
would need to be at least 24-32 gallons in size. This rule is
conservative, but works really well for small fish in the 1-3 inch
size range. Feeding should be moderate, and as a rule of thumb,
small community fish need a 'portion' of flake about the size of
their eyeball each meal. Feeding once or twice a day is fine, and
for fish like Platies especially, just letting them graze on algae
(or softened vegetables, such as spinach, peas or
cucumber) is a fine way to round out their diet. Overfeeding fish
doesn't kill them by poisoning them or blocking their stomachs or
something, but too much food does mean the filter is working harder,
and as you can see, the end product of filtration, nitrate, isn't
non-toxic. That's why we do water changes every week or two: to
dilute that nitrate. Fast-growing plants (such as floating plants if
you have indifferent lighting) can be
really helpful too, since plants absorb nitrate.>
The pond was the same. I saw a De-nitrate water additive.
<Don't waste your time with additives. Water changes do a massively
better job, for much less cost. Honestly, while there may be niche
applications where denitrification is relevant to freshwater
fishkeeping, there's
otherwise no reason to get bogged down in this side of things.
Instead limit stocking, ensure the tank is nice and big, don't
overfeed, and do regular water changes. That's all you need to do,
and it not only works well, but doesn't cost anything!>
Annette
<Cheers, Neale.>
Ammonia, Nitrite & Nitrate Units of Measure
4/10/18
Hello Crew,
<Hey Ray>
I have a 210g, probably considered overstocked, mixed Malawi tank. The
tank is filtered by a submerged media sump with a six times turnover. I
use Hanna meters for my chemistry checks. The ammonia, nitrite and
nitrate
meters all measure using the -N unit of measure (NH3-N, NO2-N &
NO3-N).
The unit of measure for ammonia and nitrite are not relevant since the
goal of both is to maintain 0ppm. Nitrate is the one causing me some
thought. The tank consistently runs 10 - 30ppm NO3-N and I use this
value to determine water changes, as it approaches 30ppm I do a 50% WC
usually every other week. But if I apply the conversion factor
(4.4) to these numbers my ranges are 45 - 130ppm in which case my WCs
should be happening probably twice per week. I recently read
the article, Nitrates in Freshwater Aquarium Systems
by Bob Fenner, which stated "Do check your test kit though almost all
are nitrate ion types on the market nowadays..." I'm guessing doing the
conversion on NO3-N > NO3 is what I should be looking at.
<Yes; agreed>
The tank has been running in its current configuration (mixed Malawi)
for 2 years, before that it was a planted discus tank for maybe 8 years.
Being retired gives me time to think, maybe too much. Should I take the
attitude, "if it ain't broke, don't fix it?" Looking for
confirmation/disagreement.
Thanks,
Raymond M Sugel Sr
<Were it me, mine, I would increase the number/frequency of water
changes as you state (twice a week; with pre-mixed (for pH, salts if you
use them) stored water. I encourage you to look into the possibility of
tying this
tank in with a good size/volume sump as well, perhaps growing live
plants there, incorporating a deep sand bed for denitrification;
utilizing and out-gassing the excess NO3. Bob Fenner>Black Ghost Knifefish; hlth., NO3 file
11/24/17
Hello Crew,
Stumbled onto your site, read some stuff that sounds very helpful.
<Okay>
I have a large about 30cm long single BGK fish, I had it now for a few
years in a 645Ltr. mostly African (both Tanganyika/Malawi) a pair of
buffalo heads, clown loaches and Chinese Glass cleaners.
<Quite a mix>
All doing well.
At one stage awhile ago I was concerned about Nitrate/ Nitrite but have
given up, could not get it right, hence small regular water changes,
water always clear, no diseases, fish have been happy, some have bred
For some reason I have noticed BGK with swollen belly not eating, see
him more often than not. Hangs vertically near the water outlets from
the filter & not in usual hiding hole. BGK fish was large when I bought
him, could he be getting old? But why the swollen belly?
<Perhaps "just" over-eating... could be a blockage, tumor... even a
bacterial et al. infection>
I would greatly appreciate any advise regarding my Black Ghost Knife
fish, he’s cool.
Regards
Gavin
<I'd read on WWM re NO3; endeavor to keep it under 20 ppm via various
methods, introduce a "laxative" food item (e.g. Daphnia, Artemia) to the
BGK for a week or so. Bob Fenner>
Re: Black Ghost Knifefish 11/29/17
Thank you Bob,
<Welcome Gavin>
Knife fish died. I'm thinking tumor or blockage. I don't feed fish for
days at a time sometimes due to shifts I work.
<I see>
Appreciate you getting back to me though.
Thanks again
Gavin
<Thank you for this follow up. BobF>
Re: Black Ghost Knifefish; now Nitrate f' as well 11/29/17
Hey Bob,
Any tips for getting the Nitrate down?
<Ah yes; avoidance from the get go, water changes, biological
amelioration, chemical filtrants. Gone over in detail here:
http://www.wetwebmedia.com/fwsubwebindex/fwnitrates.htm
and the linked files above>
It's got me beat, the Ammonia reads 0 ppm to 0.25 ppm if that, as I
stated previously I do regular water changes, vacuum the substrate but
the Nitrate stays up.
Have tried a little bit of Poly-Filter about the size of the Ammonia
Test kit box as recommended by the Aquarium place I bought it from.
<A worthy product>
But if the fish (Electric Yellow & leleupi) have laid eggs their got to
be happy right?
<That or stressed; either end of the spectrum elicits reproduction,
reproductive behavior>
Up until the Black Ghost Knife fish became crook I've had no problems.
Regards
Gavin
<And you, Bob Fenner>
Re: Black Ghost Knifefish 11/30/17
Thanks again, Bob really appreciate your help.
I will have a read of that site you forwarded.
Kind Regards
Gavin
<Real good mate. BobF>
Re: Black Ghost Knife fish; Nitrates f'
12/2/17
Righto' Bob,
Sorry to annoy you.
<Not an annoyance Gav. We're here to share>
I read the literature on the web site you forwarded, even though it
mostly spoke of Marine set ups, it did in parts touch on Fresh water and
in part mention the filter system.
That got me thinking do I NOT clean my filter regularly enough? Is the
filter the reason my Nitrate/Nitrite is high?
<This is definitely a possibility as source of NO3. Mechanical filter
media, accumulating materials that can/do break down into Nitrate is a
principal source of this nitrification product>
All most people say is do regular water changes.
I am under the impression don't mess with the filter, clean it when you
notice the flow rate drop, say every 6 months.
<Mmm; well; we need to expand on our ideas, terms here. "Filtration" is
a very large concept; for instance, it encompasses denitrification, a
set of processes "in reverse" that convert Nitrate largely to Nitrogen
and Oxygen... under anaerobic conditions. Are you aware of this?>
I use an Aqua Pro 2200 Canister Filter. The 3 sponges & wool in the
bottom basket, the rest filled with Biohome Standard Media and a tray of
BioBalls which is all suppose to allow for colonisation of bacteria's
and alleviate
Nitrate/Nitrite problems with less cleaning time.
<Actually... you may want to investigate a bit more here. I would switch
out the Bioballs and if you have more of the Biohome Standard Media or
other sintered glass (e.g. Siporax) filter product, use it in the
BioBalls space. These balls drive the forward reactions of nitrification
too much, too fast. You will likely see a difference on their removal,
substitution within a few days>
Should I be cleaning the filter more often? Have I got the filter set up
wrong?
<Just the BioBalls part here>
In the tank it's self are two air stones (bubbles/water movement), a
sponge filter, an Aquael Turbo Filter 2000 internal filter and I use it
with just the sponge like a power head pointed from one corner of the
tank to the
width of the tank so no dead spots (2 Ft..) more bubbles/water movement,
right? Also an Eheim streamON+5000. Optimum water circulation with a
natural, smooth current formation.
As I have stated previously, the fish seem happy, there colour is bright
except for one has dulled since I bought him (was red, now more brown)
one has completely change to a better colouring, Nice dark blue with a
bright
yellow streak from his mouth through his Dorsal fin to his tail (a Hap).
There is lots of water movement and air ration in my tank I think Bob,
so is the filter the problem? What do you think?
<Fishes and non-fish aquatic life can become accommodated to higher NO3
concentration over time... but I would still aim for a reasonable
number. There are other mechanisms to control; e.g. live plants use,
Deep Sand Bed (in the tank or a tied in sump/refugium), ....>
Once again, again thank you for your knowledge/ information.
<Like tools rusting in a basement, only worthwhile if employed eh?>
Kind Regards
Gavin
<And you Gavin. Do write back if something is unclear, incomplete, or
you have further questions. Bob Fenner>
Re: Black Ghost Knife fish; ongoing... NO3 12/6/17
Hello Bob,
<Gavin>
I read the literature on the web site you forwarded, even though it
mostly spoke of Marine set ups, it did in parts touch on Fresh water and
in part mention the filter system.
That got me thinking do I NOT clean my filter regularly enough? Is the
filter the reason my Nitrate/Nitrite is high?
<Might be a factor; best to only clean/change out "part" of the filter
media at every interval. As an example, if you're using two units of
Chemi-Pure let's say, take out the oldest one and leave the less old
one, adding a new unit>
All most people say is do regular water changes.
I am under the impression don't mess with the filter, clean it when you
notice the flow rate drop, say every 6 months.
<Mmm; no... better more frequently. Like every month for the mechanical
media... the chemical should be switched out/some rotated for new about
this same interval>
I use an Aqua Pro 2200 Canister Filter. The 3 sponges & wool in the
bottom basket, the rest filled with Biohome Standard Media and a tray of
Marine BioBalls which is all suppose to allow for colonisation of
bacteria's and alleviate Nitrate/Nitrite problems with less cleaning
time.
<We had this convo.... I'd remove the BioBalls, use ChemiPure in the
space instead>
Should I be cleaning the filter more often? Have I got the filter set up
wrong?
<.... Yes>
In the tank itself are two air stones (bubbles/water movement), a sponge
filter, an Aquael Turbo Filter 2000 internal filter and I use it with
just the sponge like a power head pointed from one corner of the tank to
the width of the tank so no dead spots (2 Ft..) more bubbles/water
movement, right? Also an Eheim streamON+5000. Optimum water circulation
with a natural, smooth current formation.
<Okay; good to have more circulation, and aeration helps... most
canister filters are deficient here>
There is lots of water movement and aeration in my tank I think Bob, so
is the filter the problem?
<Not a problem, other than the driven nitrification from the bioballs,
but could be improved as I've stated>
Once again, again thank you for your knowledge/ information.
Kind Regards
Gavin
<Welcome. BobF>
Re: Black Ghost Knife fish 12/11/17
Hello Bob,
<Gavin>
Thank you again for your advise.
<Welcome>
I will try the Chemi-Pure and a more regular cleaning of the filter.
So many people tell you different things, for me it's very confusing.
<Mmm; don't allow it to be. SEEK to understand the underlying science;
question opinions>
I will let you know the results. Until then Merry Xmas & Happy New Year
Bob.
<And you and yours. BobF>
Kind Regards
Gavin
Re: Black Ghost Knife fish
1/24/18
G'day Bob,
<Gavin>
Just giving you a little feed back about my aquarium as I said I would.
<Ah, thank you>
While waiting for the delivery of the Chemi-Pure I ordered online I
shopped around looking for it.
One aquarium shop had a big sale on De-Nitrate and told me it would do
the job. So I cleaned the filter, added De-Nitrate to the filter, made a
small water change, left the aquarium to settle tested the water.
Ammonia reading = Perfect. Nitrate = SKY HIGH, so I'm thinking you rip
off barstaaards.
<Mmm>
Chemi-Pure arrives, clean the filter add the Chemi-Pure & leave in the
De-nitrate, do another small water change, after a couple of days,
Ammonia reading = Perfect. Nitrate = right up there again. So then I
take everything
out of the tank, flush it all clean, find buffalo head cichlid eggs in
one rock in their area, take out nearly all the water vacuum the
substrate , put the tank back together leave it to settle, Ammonia
reading = Perfect.
Nitrate = same - NO change high as a kite. THOUGHT BUGGA THIS, took a
water sample to a pet store, they tested it for me, guess what? Every
thing Ammonia, PH, Nitrate and a fourth thing (can't remember) PERFECT,
SHOCKED AND STUNNED, obviously I have a faulty Nitrate kit, although it
doesn't expire until 2020. Get this the wife says told ya so..
<Ahh, good that you checked the checker>
All that worry, money wasted, time spent goggling and seeking advise all
for nothing, so obviously the Black Ghost Knife fish and a Peacock
Cichlid both died (a couple of months apart) with swollen bellies had a
Parasite or something happening.
Anyway the aquarium is crystal clear like the fish are suspended in air,
I'm a lot more satisfied, I have left the filter media as is:- sponges
and wool in the bottom basket, then the Marine home bio balls with
De-nitrate in the next basket, then the Bio-home filter media mixed with
De-nitrate, in the top basket is the Chemi-Pure also mixed with the
De-nitrate, there was a lot it and I still have one bag of it unopened.
<Good; best to rotate one unit out (the older) and replace it w/ new
every month or so>
Now I will leave the filter alone for awhile, but I will order some more
Chemi-pure ready for when the current lot expires. Eventually the
De-nitrate will expire as well.
Have a good one Bob and many thanks.
<Cheers Gavin. Bob Fenner>
Stress from Water Change Worse than having 20ppm Nitrates in
new Tank? 10/11/17
Hi Crew,
<Helen et al.>
I'm new to fish-keeping but have done a lot of research and hope I have
got my aquarium off to a good start. I cycled it for six weeks
using a fishless cycle with fish food for the ammonia source. I
have a 20 gallon freshwater tank with two male Dalmatian mollies, 4
female Dalmatian mollies and two female gold mollies. All but
one are less than 1 inch in size, so quite young. I know I may need to
move them to a bigger tank in the future. They have been in the tank for
eight days and I did a 25% water change four days ago and plan on doing
one every week.
<A good interval and percentage. Best to store the new water in advance
of your weekly changes; do whatever you intend to supplement (add
salt/s, alkalinity...) ahead of time>
I have been testing the water everyday using the API water test kit.
Today's readings were: Ammonia:0; Nitrites: 0; Nitrates: 20; PH 7.6.
Temp is 78.4F.
I know mollies are particularly sensitive to nitrates, so I would like
to do another 25% water change today to get the nitrates down. However,
I have also read that all fish are sensitive to changes in water
chemistry so I
am wondering what would be most harmful to the fish - having the
nitrates at 20ppm or doing a 25% water change.
<You are right to be concerned here. As you hint/state there are
trade-offs in doing too frequent/serial dilutions, and just tolerating
nitrogenous et al. accumulation>
I would also like to add some aquarium salt to the water but am again
hesitant to change the water chemistry too
much when they have only been in the tank for eight days.
<I WOULD go ahead with the salt addition/s... some every day. This will
also reduce the Nitrate toxicity>
Your advice is much appreciated!
Helen
<And gladly rendered. Bob Fenner>
Nitrate... 10/6/17
For Neale Monks and Bob Fenner
Hello again friends,
<Byron>
I’d appreciate your comments and reasoning about a question involving lowering
nitrate. I will start by saying that I understand that nitrate like ammonia and
nitrite is toxic to fish, though at much different levels/exposures and
depending upon species or age of the fish (fry being more susceptible) [please
correct me if I am incorrect here or anywhere else].
<This is correct; though the mechanisms, pathways if you will, for
poisoning/toxicity of these nitrogenous compounds are different. NO3 in
particular can be accommodated; i.e. much higher concentrations can be tolerated
with long exposure>
Consequently, if one discovers nitrate levels in an aquarium are high, say 160
ppm [I am using an actual case from my work on TFF, and this is a stable state
not something sudden], immediately reducing the nitrate to safe levels (under 20
ppm) is not in itself going to harm fish.
<Usually; yes>
I have been challenged on this, with the suggestion that the nitrate should be
lowered gradually over days or weeks, similar to other adjustments.
<Mmm; no. Immediately lowering NO3 concentration is advised>
The idea apparently is that “old tank syndrome” is dangerous and rapid changes
can be fatal; but I would respond that the danger with this is due more to pH,
and ammonia being ammonium in acidic water and the sudden change to basic pH (pH
shock, plus ammonium converting to ammonia) is the problem, not nitrates
decreasing. My argument is that nitrate is not like other adjustments (GH, pH,
temperature, or whatever) and being toxic the sooner it is lowered the better.
<I concur>
I maintain that any toxin in the water, be it ammonia, nitrite, very high
nitrate, substances released from wood or rock that are detrimentally affecting
fish, etc, are best corrected rapidly via significant water changes.
Comments please, with thanks.
Byron Hosking.
<Will ask Neale for his separate response here. Bob Fenner>
Re: For Neale Monks and Bob Fenner: Nitrate
10/7/17
Byron, Bob,
<Neale>
I don’t have any real insight into this. But I do wonder if there are
differences between species and when comparing marine with freshwater fish. My
point being that generalist freshwater fish are able to handle bigger water
chemistry changes than more specialist species (or most marines) given they’d be
exposed to such in the wild. For example, the pH of a pond can vary between
around 7 to as high as 9 once photosynthesis kicks in and dissolved CO2 is used
up.
<A useful point/speculation. I do think there are differences between
salt/fresh, young/old, acclimated and not species, specimens. Have been to
public aquariums that fed huge amounts of food to very large animals... that had
thousands of PPM of NO3>
I’ve read before that the idea we can meaningfully acclimate fish to slight pH
changes is actually erroneous anyway. The “float them in a bag for an hour” or
“drip water into a bucket for an hour” approaches sound good, but supposedly the
actual physiology works far more slowly than this. So for fish to actually adapt
their blood chemistry (or whatever) actually takes far longer, and what we’re
really dealing with is the degree to which fish can tolerate abrupt changes
(i.e., shock) and then slowly adjust across days or weeks. Does this sound
familiar to either of you?
<Yes; it does>
I do believe, Byron, that there’s a hierarchy of stress factors, and sometimes
to minimise a severe stress (such as nitrite, ammonia or extremes of
temperature) you may have to increase a mild stress (such as small pH or
hardness changes) simply through doing water changes. Of course the standard
advice should remain that water changes need to be made with water as similar to
the conditions in the tank as practical.
So far as I know, nitrate toxicity hasn’t really been studied across a wide
range of ornamental freshwater fish, but experimentally with things like
goldfish you really do need quite high levels (100+ mg/l) to cause immediate
health issues. In such situations, I think doing moderate water changes across a
few days, rather than one giant water change, might be safer in terms of
minimising sudden pH, temperature or hardness changes. But that said, if the new
water was similar enough to the old, doing 90% water changes has been
demonstrated to be perfectly safe in and of itself.
Anyway, keep me posted with what you learn!
Cheers, Neale
<And you, BobF>
Re: For Neale Monks and Bob Fenner
10/7/17
Thanks Neale and Bob.
<Welcome>
So what I take from both of you is that with the proviso that parameters (GH,
KH, pH , temperature) are close enough to be called the same, a large water
change to reduce nitrate from 160 ppm down to 10 or 20 ppm is not going to harm
the fish, and is more advisable than doing smaller changes over weeks. I will
assume my understanding is correct unless you say different.
<This is a good summation>
I do appreciate the benefit of your experience and knowledge on these issues.
Byron.
<Welcome. BobF>
Re: For Neale Monks and Bob Fenner /Neale
10/7/17
I would 100% agree with this.
Triage of any kind is about balancing the big dangers against the minor
stresses.
Cheers, Neale
0 ammonia, 0 nitrites, 160 ppm nitrates during fishless cycle
5/5/16
I am trying to cycle my 10 gallon tank (for a Betta) using the fishless
ammonia method. It's been 6 weeks and ammonia and nitrites
spiked and the fell to zero.
<Ahh; done>
My questions are: why are the nitrates so high,
<Conversion....>
do I continue to dose with ammonia (I have stopped)
<Stop>
will the nitrates drop eventually like the ammonia and No3 ?
<Mmm; slowly; yes; but better to either add some live plants... or do a
significant water change... half the water, halve the NO3>
I have just done a 90% water change and nitrates are at 40 to 80 ppm.
The tank has a HOB filter, a sponge filter with airstone, a heater and a
UV sterilizer. The pH is 7.4, the tap water is hard (and 10-20 ppm
nitrates).
There are some (3) plants and the roots of a philodendron in the tank. I
plan on adding more plants. What do I need to do?
<Really; just be patient; time going by... Monitor/test every few
days... NO3 will "go down".>
Thanks!,
Eve
<Welcome. Bob Fenner>
Re: 0 ammonia, 0 nitrites, 160 ppm nitrates during fishless cycle
5/6/16
Thank you Bob Fenner!, should I be feeding the bacteria with fish food
until the nitrates come down (just bought 4 more plants)?
<Yes; but really... "just a pinch" or a single flake or two per day.
Takes very little to sustain a nitrifying population>
Thanks again,
Eve
<Again welcome. BobF>
Re: 0 ammonia, 0 nitrites, 160 ppm nitrates during fishless cycle
5/6/16
Great, thanks again for the info.
<Cheers Eve. B>
For Neale Monks, Nitrates 1/8/16
Hello Neale, and my best wishes for the New Year to you and yours.
<Thank you.>
I will be emailing separately my observations on the flashing/bacterial issue
you helped me resolve (thank you so very much) but now I would like to discuss
nitrates a bit if you would be so kind. I have frequently read your advice on
keeping nitrates below 20 ppm, and naturally I recommend the same when I respond
to members of the forum I am now on. I am being questioned on this, so I would
like to understand it better.
<Sure thing.>
First thing to get sorted is the unit being used. The scientific community tends
to use NO3 N-n, whereas most hobby test kits use total nitrates. I understand
the conversion factor is 4.43, so for example the US EPA limit of 10 ppm
allowable nitrate in drinking water which is NO3 N-n would equate to 44.3 ppm
NO3 with our test kits. When you are recommending 20ppm as max for nitrates, is
this the hobby test kit unit (I assume so)?
<Correct. No point citing something people can't (easily) measure at home.
In fact it doesn't usually matter what numbers you choose to use. Most of the
nitrate kits I've seen will have some sort of card with them, and that card will
be have on it a scale made up of a few coloured patches. The API one for example
has seven coloured patches, from yellow (low) to red-brown (high). So long as
you aim to keep nitrates closer to the low end of that scale where sensitive
fish are being kept, and certainly below the medium colour/number on that scale,
you're laughing. Actually knowing what the numbers are is not important. So for
that API kit, yellow or orange are fine, red not good for sensitive species like
dwarf cichlids, and red-brown probably too much, long term, for anything, at the
very least a triggering factor for algae. Make sense?>
To the nitrates, then. Natural habitat waters of all of our fish (so far as I
know) have nitrates so low it would probably be impossible to measure them with
our kits.
<More or less, yes.>
In the fish, nitrate will act much like nitrite, making it more difficult for
the blood to carry oxygen.
<So they say.>
I have come across studies, admittedly on mainly commercial fish and not
ornamental, suggesting nitrate levels of 2 to 4 ppm NO3 N-N would affect the
development of fry, and many fish and invertebrates will have difficulty with
nitrate at 10 ppm NO3 N-N. This study is here:
https://www.researchgate.net/publication/8063535_Nitrate_Toxicity_to_Aquatic_
Animals_A_Review_With_New_Data_for_Freshwater_Invertebrates
You have mentioned cichlids likely being affected at levels above 20 ppm, and on
the cichlid site it is suggested that nitrate above this may be the true cause
of Malawi Bloat.
<Correct. That said, nitrate is complicated. The lethal level of nitrate for
some fish experimented on (in labs) seems to be high, supposedly 100 mg/l or
more. On the other hand, scientists have only tested a very few (big) species,
farmed trout for example, and often their experiments are shorter term things,
like how many of the fish die across, say, a week or a month. We're keeping a
hundred different species often for years if not decades, so our experiences
(and expectations) are different.>
The above is just so you have an idea of where I am with this issue. I guess at
this point, I would be interested very much in your thoughts on this, and any
evidence, studies, etc., to support our position [I have certainly taken yours ]
on keeping nitrates low.
<It's complex. Nitrate isn't something I worry about too much keeping the sorts
of fish I like to keep, such as catfish and freshwater livebearers.
Provided other parameters are good, fast-growing plants keep nitrate levels low
enough risk of toxicity isn't an issue, and water changes can be carried out
as/when required. But if I was keeping species like Dwarf Cichlids or Mollies
(in freshwater) that are known to be sensitive to nitrate, in the sense that
high nitrate has been associated with disease (bloat, shimmies, etc.) than I'd
make more of an effort to monitor nitrate and pre-empt any high nitrate
situations using low stocking, low food input, and frequent water changes. Most
freshwater aquarists can, I think,
ignore nitrate unless they're (a) struggling to keep a possibly sensitive
species; or (b) dealing with an algae problem.>
As always, looking forward to your wisdom, and with sincere appreciation.
Byron.
<Hope this helps; by no means an expert! Cheers, Neale.>
Re: For Neale Monks, Nitrates 1/8/16
This is great, thank you Neale. Now I have some follow-up, concerning the
effects/symptoms of nitrate on fish.
<Sure.>
Many if not all of your answers to questions on PFK where nitrates are mentioned
as being high involve lowering to no more than 20 ppm. From this I would assume
that the effect of nitrate is much like so many things--a source of stress,
weakening the fish, opening up opportunities for more serious problems.
<Correct, so far as I can tell. Nitrate isn't immediately toxic like
ammonia or nitrite. On the other hand, because high nitrate levels often go
hand-in-hand with things like overstocking and infrequent water changes, it's
hard to pick out any problems nitrate is causing from things like lack of oxygen
and background acidification cause by nitrate and phosphate accumulation. Tanks
with high nitrate levels tend to be neglected tanks, in the sense that the fish
keeper has too many fish in them and does too few water changes. So there can be
all sorts of reasons fish in those tanks are stressed, not just the nitrate.
Make sense?>
One obvious that I assume would occur would be a shortened lifespan from the
stress if nothing else. But are there any signs along the way that nitrate may
be causing issues?
<None that I'm aware of, but some diseases have been associated with high
nitrate level, such as Hexamita and HITH/HLLE in cichlids.>
A member on the forum today mentioned his fish being "fine" with 80 ppm nitrate
(which is way into the red on the API card you mentioned) but his Firemouths
remained quite pale, and he wondered if this was due to the nitrates. I would
think this likely, do you agree?
<It's certainly a possibility. But I'd also observe that Firemouths are widely
kept badly. Though territorial, they're bluffers, not fighters, and do badly
with genuine fighting cichlids (pretty much all the Central Americans beyond
Rainbow Cichlids) and are really best kept on their own with dissimilar
tankmates (catfish, loaches, characins, etc.). They're also sand-sifters, so a
tank with gravel would be wrong. Finally, like all cichlids, their colours will
become paler if they're exposed to bright light from above and/or below. A dark,
shady aquarium is better.>
Cheers,
Byron.
<Cheers, Neale.>