Please visit our Sponsors
FAQs on Marine Freshwater Quality involving Nitrates: Troubleshooting/Fixing

Related Articles: Nitrates in Freshwater Aquariums, Establishing Cycling, Freshwater Filtration, Know Your Filter Media, A Concise Guide to Your Options by Neale Monks, Setting up a Freshwater Aquarium, Tips for BeginnersWater Quality and Freshwater Aquariums

Related FAQs: Nitrates 1, Nitrates 2, & FAQs on FW Nitrates: Importance, Science, Measure, Sources, Control, Chemical Filtrants, & Ammonia, FW Nitrites, Biological Filtration, Freshwater Nutrient Cycling, Establishing Cycling 1,


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.
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>
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!
<And gladly rendered. Bob Fenner>

Very high nitrate readings          12/6/16
I have a really big problem with nitrates in my community tank and I am wondering if there was anything you could suggest that would help. The current readings for my 240 litre tank are Ph 7.6, Ammonia 0, Nitrite 0 and Nitrate 160.
My readings in my tank were Ammonia, 0, Nitrite 0 and Nitrate 30. I have plants in my tank and after research I decided to add liquid carbon to my tank as I was led to believe it was good for the plants.
<I'm not a fan. Here's my take: unless your plants are obviously failing, it's best to let them adapt and thrive in ambient conditions. Adding a bit of plant fertiliser for iron and magnesium makes sense, but that's about it. Only after careful consideration would I ever recommend adding CO2, and such tanks are usually designed around the plants, not the fish, so tend not to be suitable for casual fishkeepers. Since plants 'fix' carbon in the form of CO2 into glucose via photosynthesis, the limiting carbon source for them is normally CO2, which adding CO2 relieves a bit. But adding a carbon-based compound such as glucose or alcohol doesn't really seem to make any sense to me. Plants don't absorb these directly, and if it does solve some particular problem, that has to be a very niche situation. Best avoided, otherwise all that happens is the increased nutrients in the water spurs a bacterial bloom into being, and that in turn places more strain on the biological filter (with consequent decline in water quality).>
I have 12 tanks and I added the liquid carbon to my 240 litre community tank and my 125 litre Betta sorority tank. I tested the water a couple of days later and the readings were fine. After about a week of using the product my plants started dying off and I noticed some of the smaller fish, galaxy Rasboras and emerald Rasboras were struggling and starting to die. I tested the water and my Nitrates had gone sky high. I tested the water in my other tanks. The Nitrates were sky high in my sorority tank too. My other tanks were fine. The only change to these two tanks was using the liquid carbon. As the plants were dying and the cover for my small fish was disappearing I went out and bought £50 worth of new plants which was about 12 plants and added them to my tanks and started doing 20% water changes daily.
<Yes, understood; but in situations where fish are dying, toxins/poisons are a bigger issue to deal with than pH/temperature fluctuations. So bigger water changes, even 75%, are not out of line, provided you keep the temperature more or less steady and avoid massive water chemistry changes (this latter a reason why I recommend keeping fish adapted to your local tap water conditions rather than relying on RO mixtures you can't make in large quantities when required).>
I stopped using the liquid carbon.
Again the plants started dying off and I have now lost all my galaxy and emerald Rasboras and some of the other smaller fish.
<Do think these are unrelated. Plants can die off when uprooted/replanted, but usually recover. I've seen a massive die-off of Vallisneria when the pH dropped in one tank, so unstable water chemistry could be an issue.>
My Betta that was in the community tank started to struggle and I quarantined him. He is now doing fine. I carried on with the water changes and replaced the plants again last Thursday. The readings in my sorority tank have stabilised and are now Ammonia 0, Nitrite 0 and Nitrate 5 (Nitrate has never been so low). My community tank though is just not changing. The Nitrates just do not seem to be going down at all. I don't overfeed the fish and clean out the waste regularly.
<Change more water; siphon/remove any/all dead and decaying material, including plants. Be ruthless. Nitrate doesn't come out of nowhere -- it comes out of decay. So clean the tank, and also look at any other places detritus might be found, like filter media and the inside of filter hoses.>
Prior to this I was doing 25% water changes weekly and siphoning up waste on the top of the sand. Even though I have spent a fortune on plants most of them have died.
<Understood. Stabilise water quality first. Ensure the fish are healthy. Rebuilding a planted tank takes time after this sort of crisis. Don't rush it. Even a few, temporary, floating plants could provide nitrate remove as well as shade and shelter.>
I don't want to keep on buying plants that are going to die even though I know they absorb Nitrates.
<When they're growing, at least.>
My tank has 18 Tetras (Rosy), 6 Harlequins, 9 Honey Gourami's, 8, Cory's, 2 Synodontis Petricolas (not adults), 2 Bristlenoses (not adults), 6 Danios and 2 Synodontis Eupterus (not adult) and 4 Threadfins (was 6 before), 14 Rasboras that have died.
Thank you in advance
<Hope this helps, Neale.>

Re: Very high nitrate readings         12/6/16
Thanks for your quick response.
Last night we did a 50% water change. Took all the bog wood, caves out etc.
Made sure there was no waste or decaying plants underneath, cleaned the filter out. I forgot about the pipes so when I turned the filter on (external) it spewed out some rubbish.
<Ah, yes!>
It was very late so I went to bed and tested the water again this morning.
The Nitrate was still 160 so I cleaned out the pipes, cleaned up again and changed another 90 litres of water. Just tested the water and it is still the same.
<Would perhaps double check two things. First, your tap water. What's the nitrate reading there? If you have, say, 160 mg/l in the aquarium, and replace 50% of the water with tap water with 0 nitrate, you should get 80 mg/l if you do a nitrate test afterwards. Of course few people have zero nitrate tap water, but it should certainly be no higher than 40-50 mg/l even in cities. So a substantial should yield a big reduction in nitrate.
Second thing to do is check your nitrate test kit. It may be off. It may be out of date, difficult to read, or whatever. I tend to go by gut instinct.
If the fish are fine, I assume the water is too. Clearly, this hasn't been the case for you, but if you "deep clean" the tank, and then remove half the water, water conditions should improve a lot. If nitrite and/or ammonia are zero, I'd be especially skeptical of wildly high nitrate levels after big water changes.>
Apart from continuing with the water changes would adding extra media to the filter or adding an internal filter help to stabilise the tank?
<No. Biological media removes ammonia and nitrite. They have no positive effect on reducing nitrate levels, because denitrification requires anaerobic conditions you won't have in a standard aquarium filter.>
Are Nitrate removing sponges helpful?
<Can be, but very expensive, and don't do anything a water change doesn't. So a niche product. Not what you need here.>
Also do you think that the readings for Nitrate are actually higher since the test kit has 160 as top on it's chart and that is why water changes aren't actually showing any improvements.
<Again, change lots and lots of water. If you change half today and half tomorrow, by rights even crazy high levels should be back down to normal levels. Bear in mind 100 mg/l is considered toxic, so levels 160 or higher are very unlikely.>
I hate dirty tanks and I siphon up the waste in the tanks all the time. I hate to see poop and dead leaves sitting on top of the tank. I have added a photo. Is there anything you would add or take out that might help.
<See above.>
Thank you again Neale.
<Most welcome. Neale.>

Re: Very high nitrate readings     12/7/16
Just tested the tap water and the reading is 5ppm.
If I didn't use the same test kit on my other tanks I would have suspected that the kit wasn't accurate too.
My other tanks don't show high readings so I don't know why the readings in my community tank aren't going down with the water changes.
<There's some reason nitrate is being produced in this tank, very quickly.
Could be mineralogical, i.e., a nitrate salt, rather than a waste product.
Have you added something that might be responsible? Like a holiday feeding block? Or some type of organic remains, like a skull or seashell? If the tank is clean; if you have done multiple water changes; if the fish look fine -- I'd tend to ignore the test kit. Let things run for a few days, see what happens. Cheers, Neale.>

re: Very high nitrate readings    12/8/16
The only thing added recently other than the liquid carbon is an extra piece of Mopani wood.
<'Post hoc, ergo propter hoc' is often misleading, but if the nitrate shot up after you added this wood, I'd remove it. Do big water changes, then see if it stays lower, at more normal levels. If it does, there's your issue.>
The tank has soil which I have always had in the tank and about an inch and a half to two inches of sand over the top. It has one ornamental cave and various pieces of Mopani wood (bought from the aquarium section of a big brand shop) that has been soaked in boiling water before adding. All but one big piece has been in the tank months. I have some plants in the soil and Amazon Frogbit (even most of that died off after adding the liquid carbon) so I have no idea what would cause the levels not to go down. <Agreed. Would review the substrate for anything buried in there, but still... not convinced.>
It probably sounds stupid but can it be locked into sand and possibly be released in cleaning?
<Anaerobic decay can occur, the gases become trapped, and then released 'of a sudden'. But this normally hydrogen sulphide, and in reality, is pretty rare. Marine aquarists invariably have deep substrates and anaerobic live rocks in their tanks, and don't worry much about it, and their fish are far more sensitive. Similarly ponds with their black oozes. That said, if you had a big dead fish in the substrate, that could be an appreciable risk.>
Other than setting up a different tank I have and moving the filter and fish to it I don't no what else to do. I have had two more fish die today.
<Oh dear. Hope this improves. Cheers, Neale.>
re: Very high nitrate readings    12/8/16

Update: I have just taken out approximately 80% of the water and changed it. The reading for Nitrate has not changed at all. I have now been taking huge quantities of water out daily and it doesn't appear to be doing anything to help.
<This is all very odd. Do you have a temporary tank? If this was me, and I know this sounds like a lot of work, I'd strip the tank. I'd deep clean the filter (though not kill off the bacteria in the process). I'd leave out all the rocks, sand, plants, etc. Only thing in the tank would be simple, easy to clean ornaments like flowerpots or ceramic doodads. Let the fish settle.
Hopefully water quality should be excellent. I'd then rebuild in stages, each time seeing what happened for a few days. Maybe float the plants without substrate for a day or two, and see what happens. Then add some substrate (ideally, new). Rinse and repeat! At some point you'll find what's wrong. Or maybe it'll all vanish. It is possible for tanks to go
toxic for some reason, and stripping and rebuilding solves this. Make sense? Cheers, Neale.>

Re: Very high nitrate readings   12/9/16
I decided to give it one more go at water changing the night before last.
Took 145 litres out. When I tested the water it was just slightly lower than the 160ppm but because it was the first time it has gone under that reading I did another 145 litres and the water tested to under 40ppm. It has been hard work doing such large water changes every night but at last we have progress.
<I'll say! Yes, very hard work. This is NOT normal for fishkeeping, thank heavens!>
I definitely will never add liquid carbon to my tank again.
<Indeed. I have no idea what the problem was/is, but agreed, total nightmare.>
Thank you so much for all your help.
<Most welcome and good luck, Neale.>

Nitrate levels high - how to fix?– 6/24/13
We have a 20 gallon tank with a variety of 4 small fish. We originally had 6 but 2 died last week. We've had the tank since February so it's had time to cycle. The 2 that died would shimmy in place and then lay on the floor of the tank. Today we have a fish that is darting around the tank.
<Darting and shimmying behaviour sounds like New Tank Syndrome. Cut back feeding to zero for the next few days. Do daily water changes of around 20%. Check the filter is properly working (e.g., water flowing) and if you clean the filter, be very careful not to harm the filter bacteria by rinsing the biological media in a bucket of aquarium water rather than under a tap.>
Our Nitrate levels are obscenely high despite regular water changes (cleaning from the beneath the rocks).
<What's the nitrate out of the tap? If your tap water has a nitrate level of 20 mg/l, but the aquarium has a nitrate level of 50 mg/l, then the difference, in this case 30 mg/l, comes about as the end product of biological filtration. Reducing the number of fish in the tank, reducing the amount of food, and/or doing more water changes will all lower nitrate levels (and obviously doing the opposite will increase nitrate levels).
Adding fast-growing plants, especially floating plants, can also reduce nitrate.>
- Ph is consistently 6.6. We have not been able to get it to 7 despite regular water changes & adding: Stress Zyme, Stress Coat, Aquarium Salt, SafeStart, and Neutral Regulator
<Get the carbonate hardness tested. Acidification in the tank is natural and will always tend to lower the pH in an aquarium between water changes.
Adding something with calcium carbonate in its can reduce this; the most convenient way is to put a half-handful of crushed coral into a filter medium bag (a bit like a nylon bag) and put this into an external canister filter. Alternatively, you can add a commercial buffer to the water. Use precisely as directed. Do remember that over time acidification will use up the buffer, so do regular pH tests for the first week to see how well the buffer is buffering. You might instead use some of the Rift Valley Salt Mix, here:
Use at about one-half the dose suggested for a mixed species community tank, testing the pH and hardness, and either using less or more depending on the species of fish you're keeping.>
- Ammonia levels are at 0
- Other levels are fine
What is causing high Nitrate levels and what is the best way to handle this?
<See above; if nitrate levels are greater than the tap water, then the aquarium is generating the nitrate, and better maintenance and/or stocking will be the solution.>
We're receiving mixed messages advising a huge water change vs. don't do too many water changes.
<In short, you can change as much water as you want, so long as temperature and water chemistry (hardness and pH) stay steady. In practise changing 25% every week is about right for the average community tank with not too many fish. For casual aquarists, more frequent 25% water changes (even daily if needs be) are the easiest and safest way to avoid dramatic swings in water chemistry and temperature if you need to change more water.>
Thank you for your time,
<Welcome, Neale.>

Numerous medicinal treatments, fish still ill   4/8/13
I had been previously speaking with Bob back in November 2012 regarding my tank and fish issues, and since then I have discovered, I believe, the root of my problems, but the fish are still not well.  I understand that it may just take time, but I am writing again to see if there is anything else I can do to help the fish’s well-being. 
<Sure thing.>
I have a 10 gallon tank; when the problems first arose, in August of 2012, I had 1 Honey Gourami, 6 Corys (Peppered and Albino), a guppy and a Nerite Snail.  My nitrates spiked to 40ppm, the snail died and the tank had lots of algae.  By doing water changes, the nitrates lowered to 10ppm through the rest of August, September and October (I was doing 30% water changes per week).  Between the nitrates and the algae, I figured the filter was overburdened by the number of inhabitants, so I re-homed the guppy.  November the nitrates went back up to 25ppm.  I did a 40% water change and a week later a Peppered Cory died.  At this point, I realized the Gourami and other catfish seemed ill (sitting on the bottom of the tank, listless, Gourami with stringy poop).  I did a dual treatment of Maracyn and Maracyn 2; it did not help.  I did a 50% water change after the treatment, a 40% water change a week later, and after speaking with Bob, I then treated with Metro.  I used the Metro in the tank and also tried to feed it to the fish by attempting to bind the Metro to their food with fish oil, which kind of worked (the fish had and continue to have an appetite).  Nitrates lowered to 10ppm by December.  The fish seemed better at first, but then became sick again with the same symptoms stated above.  Then an Albino Cory got pop-eye and died.  I treated the tank AGAIN, this time with a treatment called Parasite Guard, which has a combination of Praziquantel, Diflubenzuron, Metro, and Acriflavine.  I also treated with Maracyn 2 in conjunction with this.  After the treatment, a Peppered Cory died.  The other fish improved in health, only to get sick again.  So now we have the Gourami and 3 Corys left at this time.  By mid-February, the nitrates spiked to 40ppm.  Throughout this time, I had been scaling back feedings, thinking this was causing the nitrate problem.  I did water changes as usual to lower the nitrates, and I also figured out the source of my nitrate problem, finally, which was the sinking wafers I was feeding the Corys.  I had scaled back to half a wafer a day, but upon observation, the few Corys in there were not eating this in its entirety within a few minutes.  Then it seems the wafers would get buried in the gravel.  My normal maintenance is 20-25% weekly water changes/gravel vacuuming, where I was sucking up the leftover wafers.  I thought I was vacuuming up their poop, but it was actually the wafers.  So, they stopped getting wafers by the end of February, and since they were still sick, I treated again with Maracyn 2.  Throughout March, I tested the nitrates every week and they are steady at 10ppm.  As before, the fish showed improvement with the treatment, and right now their health is degrading back down.  Same symptoms; listless, sitting at bottom of tank.  Then recently, after treatment, the last Peppered Cory died.
<I see.>
So now I have the Gourami and 2 Albino Corys.
<Definitely time to take stock, reflect.>
One of the Albino Corys looks in bad shape- it came down with fin rot previously.  The only fins left are a bit of tail, a front fin and a sliver of a front fin on the other side.  The rest are gone.  Also, with this Cory, it has an issue with one of its eyes.  I thought a long time ago that its eye was damaged.  It was just white over it.  I thought maybe the eye was gone.  But now it has changed, maybe for the better?  I can see the eye is actually there, but it’s white and smaller than the other eye.  There is also a tiny red spot in front of the eye.  Not surprisingly, this Cory spends most of its time in the corner of the tank.  It still eats, but considering the history here and how bad it looks, I was considering euthanizing him.  Maybe you have some thoughts on that?
<Nothing specific. If the fish feeds and shows signs of recovery, however slight or slow, I'd hold off euthanising it. Corydoras can, do recover from amazing stress and hardship; they're tough little spuds!>
Now the other Albino Cory, which had been the healthiest and hardiest, I just found this past Saturday morning lying on its side.  It then swam away, only to lodge itself between the air stone and tank wall, upside down.  I haven’t found it like that since, but it’s listless.  The Gourami is also listless and spending more time at the bottom of the tank.
<I see.>
So, I think the exposure to high nitrates is the problem here, although I don’t know exactly what ailments my fish have, or if they have more than one.
<A combination, likely caused by environmental stress, which can of course include medications
, some of which are outright toxic to fish, especially if used repeatedly or at too high a dose. Do bear in mind a 10-gallon tank likely holds 7 or 8 gallons of water, so overdosing is real easy to do.>
I have medicated four times to no avail, the last being only a month ago.  Since it seems the nitrates are now under control, part of me says just give it time.
<Nitrates at 40 mg/l shouldn't be a problem; that's London tap water! I'd be looking at the tank more generally, especially nitrite level as a key measurement of filtration efficiency. I'd test 4 or 6 times across a day to see if nitrites go above zero at any time, rather than just 1 time a day, and I'd also be increasing filtration as a matter of course, adding another internal or external filter as your preferences and budget dictate. I don't like bio-wheel filters, but do at least make sure yours is set up properly and working correctly. Of course, remove any carbon if medicating (medication won't work if there's carbon in the filter) and I'd also remove any chemical media such as zeolite. Maximise biological filtration, but take care to clean media as gently as possible. Your tank is relatively small, and that's likely a factor, though shouldn't have been a lethal one.>
But, they are still sick, and I wonder if they are slowly dying.  If that’s the case, I’d rather euthanize all of them and put them out of their misery.  Of course I feel horrible for my stupidity, and embarrassed my fish are in this state.  I don’t know what to do.  Would medicating even be an option again?  Any other measures I can take? 
<My gut feeling is to let things settle down. Get the big picture (i.e., water quality and filtration) sorted out. If the fish all die, then that's that, and you should scrub the tank as best you can, use a good aquarium steriliser if you can, and then start over using fish suitable for the size tank you have and the water chemistry you're working with (e.g., Endler's Guppies, Ricefish and/or Cherry Shrimps).>
Other info- Ammonia and Nitrite 0, pH 8, hard water.  Filter- Marineland Bio-Wheel Power Filter, 100 gph.
<<RMF would remove "the wheel" from this, these filter/s... A ready source of nitrate production>>
<Sounds adequate, but I do wonder. Just not a fan of this type of filter, and such mixed reports on the likes of Amazon suggest some variation in quality and effectiveness. Would heartily recommend a decent external or internal canister or failing that, plain vanilla undergravel if budget is limited.>
Temp 78 F.  I know now that Gourami’s prefer soft water and Corys prefer cooler water, but this is where I am at.     
<Quite so.>
Sorry for the long email and thank you for any advice you can offer,
<Hmm… sounds like you and your fish have been through the wars. Good luck going forward! Neale.>
Re: Numerous medicinal treatments, fish still ill... FW Filtration, NO3 f's      4/9/13

Other info- Ammonia and Nitrite 0, pH 8, hard water.  Filter- Marineland Bio-Wheel Power Filter, 100 gph.
<<RMF would remove "the wheel" from this, these filter/s... A ready source of nitrate production>>
<Sounds adequate, but I do wonder. Just not a fan of this type of filter, and such mixed reports on the likes of Amazon suggest some variation in quality and effectiveness. Would heartily recommend a decent external or internal canister or failing that, plain vanilla undergravel if budget is limited.>
<<<Bob, would you recommend supplementing or replacing with another filter?
>Yes; always a good idea to have redundancy in filtration<
Would a traditional undergravel be better than this Marineland unit?
>Mmm, better? Yes, in terms of more reliability, flexibility and continuity. Worse in terms of (historical) maintenance, NO3 issues<
My gut feeling is that undergravel filters, if used right, are reliable and inexpensive; what say you? Cheers, Neale>>>
>I do concur... mostly their downside is that folks "get lazy" with regular vacuuming/removing detritus/mulm. BobF<

Cichlids Dying Rapidly-- 03/20/11
Cichlid Tank Die Off

Hello. I have a 90gallon cichlid tank. I am running 2 Fluval filters a 405 and 305. I have sand from home depot and about 70 lbs of live rock and couple lbs of other rock. I also have a Rena air 400 for air supply. my pH is around 7.8. Nitrates are higher around 60-80ish, nitrite is 0 and ammonia is 0. I have 25 African cichlids currently from yellow labs, peacocks, scats and few others. I have never had and problem with fish dying until the last few weeks. I purchased a 4 yr old Calvus from a friend and seemed fine. The next morning I woke up and found 3 fish dead.
I immediately brought him back because I figured he killed them. They had no bite marks on them or anything noticeably wrong. Over the next couple of day I lost another 5 cichlids all were fine the day before and found dead with nothing wrong with them. It has been 2 weeks now since anything else has happened.
What could of caused the death of 8 fish in little over a week? Could the calvus had brought some sort of parasites to the tank? I keep the salinity around 1.008ish brackish. I lowered it a little thinking maybe the salt was burning their gills please help. Thanks Adam.
< Nitrates become a problem at anything over 20 ppm. Nitrates are less toxic but they are still very harmful to your fish at these very high levels. As your fish died the levels of ammonia and nitrites continued to rise and added to the problem. The new fish could not handle the nitrate level and died pretty quickly. The salt was not helpful, in fact probably inhibited the FW bacteria needed to convert the ammonia and nitrites to nitrates.-Chuck>
Re: Cichlids Dying Rapidly
Cichlids Quickly Die  3/21/11

I was able to scoop the dead fish out right away and my ammonia levels and nitrites never changed from 0. None of the fish that died were new either the tank has been set up for little over a year now. So does more salt make the nitrates higher? I am unclear about the last sentence sorry. Thanks for the fast response
< The high nitrates are the major cause of the tank crashing. The new fish could not tolerate the excessive nitrate levels and quickly died. When they died the ammonia levels had the potential to spike. This only adds to the stress. The rift lakes are not brackish. They are hard and alkaline. Salt increases the slime coat over the skin and gills. This may have made your cichlids more tolerant of the high nitrate levels. salt does not increase the nitrate levels. -Chuck.>
Re: Cichlids Dying Rapidly
Cichlids Dying Rapidly III  3/22/11

There were NO new fish added that died. And I am unsure how long the nitrites had been high for because I had never tested them. They are still high. There are still 25 cichlids and there have been no problems for about 2 weeks. I don't believe nitrates had anything to do with this because they are still high and always have been. Most people are. The ammonia and nitrites never changed.
< There are two different scenarios, sick fish or sick tank. When a fish is sick the pathogen usually only affects old or weak fish that become vulnerable to disease due to stress. A sick tank, one that water conditions are not favorable to keeping aquatic organisms in an optimum level is a sick tank that stress fish. When fish are stressed then they are vulnerable to organisms detrimental to their overall health. Nitrates in the 60 to 80 ppm is a problem. It may not have been a problem in the past but it is one now. Losing 8 fish in a week would be very rare due to a single disease. It is a sign that something is wrong with the tank. You may live in an area with high nitrates in the tap water due to living in an agricultural area where fertilizers have leached into the groundwater. Check the nitrates of your tapwater. If they are less than 60-80 then start to change the water to bring the nitrates down. You asked the question and this is the best answer based on the information you have provided. I would like to recommend the book "Enjoying Cichlids" by Ad Konings. this book will help you with all aspects of cichlid keeping.-Chuck>
Re: Cichlids Dying Rapidly
Cichlids Dying Rapidly IV   3/24/11

So the calvus may have contributed to the start of the overall health problems is that what you are saying?
< The nitrates were already very high. The additional fish elevated ammonia, nitrites and nitrates to the aquarium water. When you added the new fish it just added to the problem and the levels just reached a toxic level with the addition of the new fish sooner than if you had not added the new fish.>
He bothered no one and he was gone after the 1st day because I thought he killed 2 fish but 6 more died after he was gone.
< Big calvus can be killers if they are breeding and defending a female in a shell or protective cave. If the calvus was a killer you would have seen very obvious aggression towards the other fish.>
Nitrates out of my tap are 0 tested them and it is also the law you can get sick from nitrates if you are to constantly drink water that has them.
< There are limits to how high the nitrates can be in domestic drinking water. >
I have done several changes and nitrates have not changed.
< Your tap water is zero and the aquarium water is in the 60-80 ppm range of nitrates. A 50% water change should have cut then in half just by a matter of dilution. Something in the tank is contributing to the excessive nitrates. This week clean the filters and change 1/3 of the water. Next week vacuum the gravel and change another 1/3 of the water. Dead fish, uneaten food and decomposing plant matter can increase nitrogenous waste.
Also feed the fish once a day and only enough food so that all of it is eaten in 5 minutes. Over a couple of weeks you should see a decrease in the nitrates.-Chuck>

Sudden change in NitrAtes??? 10/13/09
I have an established and cycled tank. It's been set up for about a year now. Readings have always been; Ammonia= 0, NO2 = 0, and NO3 = 20 or so.
Suddenly NO3 is now 0?
I know low Nitrates are a good thing, but I'm concerned about the sudden change.
<So long as nitrite and ammonia are both zero, so it's not as if the biological filter has conked out, I wouldn't worry.>
At first, I thought my cycle had crashed inexplicably, but Ammonia and Nitrite have not risen at all. There are no live plants in the tank, so that can't account for the change.
<Nor can I. Most likely what scientists call a "rogue reading". Would repeat the test, and also think about possible sources of error -- e.g., old/contaminated test kit.>
It's a 29G brackish system for guppies with a SG of 1.003. Right now we have 9 guppies in there with their fry making plenty of ammonia. pH is 7.8, GH is about 300 (too high?), and KH is also 300 (also too high?).
<Both fine.>
As an aside, I've had trouble w/ pH stabilization due to low KH and I'm using a Rift Valley Salt mix recipe I got at WWM but it seems to make things stable but REALLY hard.
<You can tweak the proportions a bit if you want. Adding a bit less Epsom salt will lower the general hardness, while adding a bit less baking soda will lower the carbonate hardness. The Rift Valley salt mix is a starting point really, and you can feel free to experiment a bit to get the precise mix of general and carbonate hardness values you want.>
Any suggestions on this would be helpful.
<I wouldn't worry too much Guppies enjoy "liquid rock" and 300 mg/l calcium carbonate is about 17 degrees KH, well within their comfy comfort zone.>
Everyone seems basically happy, but they seem to be a bit more active than usual. There isn't any flashing or rubbing, however, so I'm not sure what the extra activity is about really. So (after all that) my question is, can a sudden drop in Nitrates be indicative of a problem? If so, what am I looking for?
<So far as fish are concerned, low levels of nitrate are not a problem.
There are arguments about whether near-0 levels of nitrate are useful for corals or plants, but that's a whole other issue. For your Guppies, it's fine.>
Thanks so much.
<Cheers, Neale.>

New African Knife fish not eating/RMF  10/4/09
<Hi there>
Two days ago I purchased an African Knife fish after researching for quite some time and visiting pet stores.
<Xenomystus nigri... one of my fave fishes>
I purchased a 55 gallon aquarium setup and cycled it for ten days,
<This is a quick cycle>
took a water sample to be tested, and finally purchased my knife fish. It is quite healthy (busy at night and still in the day.) It has plenty of hiding places, but does not seem the slightest bit inclined to eat. So far I have offered him frozen bloodworms, earthworms, and tropical flakes at night when he becomes active. He is about five inches and very healthy. I have searched the web diligently, finding only similar instances where refusing to eat was a problem and have read that larger knife fish can be difficult feeders. I was hoping for some suggestions on how to get him interested in feeding, because I would really hate to lose the fish I was soo keen on keeping.
<Mmm, well... am not sure this system is fully cycled, nor the fish all the way settled in...>
Thank you,
<Do try some form (frozen/defrosted, freeze-dried (stuck to the side low against the inside viewing panel/glass) or live Tubificid worms to get this fish started on captive foods... And do search again on the Net using the scientific name. Bob Fenner>

Re: New African Knife fish not eating  10/5/09
Thank you so much for responding,
<My pleasure.>
To cycle my tank, I used AquaSafe for the heavy metals and in the next ten days I fed the tank with tropical flakes.
<Well, adding the flakes should work. But I'd be staggered if it only took 10 days to cycle the tank. Three to six weeks is normal. My gut feeling is your aquarium isn't cycled, and until the ammonia and nitrite levels hit zero, you'll have some problems. Non-zero levels of ammonia and nitrite stress fish, and among other things, put them off their food.>
I had a sample of the water tested for nitrates and the man that showed me how, explained that it was at zero.
<Nitrate -- with an "a" -- is largely irrelevant here. Unless you have very high levels, freshwater fish generally don't care about nitrate levels.
It's nitrite -- with an "i" -- that matters, and above zero, this most certainly is toxic to fish.>
I will try Tubifex tonight, and hopefully he will give in.
<Would actually buy a nitrite test kit first, and check the nitrite level.>
Thank you soo much for your help!-Stephanie
<Cheers, Neale.>

Re: New African Knife fish not eating  10/5/09
Thank you for responding! I cycled the tank using AquaSafe and feeding it for ten days like there were fish in it and when I had my sample tested, the nitrates read zero,
<... actually, NO3 should be accumulating if the system is cycling...>
but perhaps he is just not quite settled in yet. I have bought some Tubifex worms and I will give these a try tonight. Thank you soo much for your help!
<Do read on WWM re biofiltration, cycling. BobF>

Re: New African Knife fish not eating  10/5/09
I took your advice and bought a good test kit, and determined the following: Nitrites are reading 0, Nitrates are 80-160, hardness is 25 (very soft), chlorine is 0, Total Alkalinity is 180-300, and pH is about 7.4-8.4 (Alkaline).
<Mostly sounds within the tolerances of this species. That said, the pH between 7.4 and 8.4 covers a lot of ground: an increase of 1.0 on the pH scale corresponds to a ten-fold increase in acidity or alkalinity. I'm assuming this test kit is one with strips: while easy to use and certainly inexpensive, they are notoriously difficult to read and consequently can be unreliable. In any case, if you can have the pet shop confirm with a liquid test kit what the carbonate hardness (alkalinity) might be, and what the pH actually is, then that would be very useful.>
Since Nitrites are zero, should I not be concerned about the water quality?
<I'm still skeptical that you were able to complete the cycle in ten days... that's really a very short period of time (unless of course you added mature filter media from another aquarium). So I'd be sensitive to
the idea nitrite and ammonia levels might not be as low as you think. Try a test 2-3 times in one day; once first thing in the morning, another immediately after feeding, and then another a couple of hours thereafter.
If these are still zero, then yes, you are probably fine.>
Will this water quality contribute to the knife fish's lack of appetite?
<I'd try and pin down the pH. Xenomystus will do fine at pH 7.5, and should remain healthy even as high as pH 8. But above pH 8, and certainly at pH 8.4, it is out of its comfort zone.>
Thank you again for helping me!
<My pleasure.>
<Cheers, Neale.>
<<I think Neale (or I) mis-read the Nitrate reading... 80-160 ppm is WAY too high. Please read here re importance and reducing: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm
and the linked files above. Bob Fenner>> 

Re: New African Knife fish not eating: MORE... & FW NO3 f'  - 10/05/2009
<<I think Neale (or I) mis-read the Nitrate reading... 80-160 ppm is WAY too high. Please read here re importance and reducing:
and the linked files above. Bob Fenner>>
<Bob, you are quite right. I missed that: in fact I've never even heard of nitrate levels that high. Stephanie, you need to do a big water change today, and another tomorrow, I'd say 50% each time. Did you do water
changes while cycling the tank? You need to, otherwise the nitrate just builds up. Don't feed the fish. Review carefully before you start feeding how much you're adding. With luck, once the nitrate drops to below 50 mg/l, and preferably below 20 mg/l, you'll find the Xenomystus behaves much more normally. Feed, sparingly, small morsels of food. Initially at least, maybe one earthworm, every other night. Cheers, Neale.>

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/05/2009
Oh, wow, I am on my way to doing a water change, but before I did, just out of curiosity, I tested the tap water and noticed that the Nitrates are equally high coming out of the tap! I have a Culligan water filter and I tested it as well with absolute opposite results... Should I consider using the filtered water instead? There were no nitrates present at all, the water was a bit softer and not as alkaline. The Xenomystus at an earthworm last night, so he is giving in, but I feel the water is still stressing him. Thank you again!
<... Please read where you were referred to. I would NOT drink this water until it is tested by a professional. I would NOT use salt-recharged filter water... ALL this is gone over on WWM. Bob Fenner>

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/05/2009
<... Please read where you were referred to. I would NOT drink this water until it is tested by a professional. I would NOT use salt-recharged filter water... ALL this is gone over on WWM. Bob Fenner>
<<Within the EU at least, the upper level of nitrate that is considered safe to drink is 50 mg/l; above that, your water supplier is *obliged by law* to act. It sounds as if your water is contaminated, e.g., by
agricultural run-off (the source of ~70% nitrate in UK water supplies, at least). As Bob says, this should NOT be treated as drinking water. Babies in particular are at particular risk (see "Blue Baby Syndrome"). Call your water supplier, now. Cheers, Neale.>> 
>A note here... Neale and I are certainly NOT trying to scare ("terrorize") anyone, nor are we "certified" health authorities of any sort... We are only trying to urge readers on to further awareness and possible action, to safeguard their livestock and safety. RMF<

Re: New African Knife fish not eating: MORE... & FW NO3 f' - 10/06/2009
Wow, I certainly will have to get someone to come out and check the water (we have a well and live near some farm fields...)
I went ahead and used reverse osmosis filtered water for my 50% water change (I would not dream of using the same tap water,) and the nitrate level is in the 30's! I may have to supplement the water with minerals, but at least this is bearable for now. Hopefully my problem is solved.
<One problem solved, and another created. Plain deionised water has zero buffering capacity and isn't suitable for fishkeeping (indeed, pure water is potentially harmful to fish). To each bucket of deionised water, add appropriate minerals to harden it up. You can buy ready made hardening salts (often called Rift Valley cichlid salts, as opposed to tonic salt or aquarium salt, which don't want). Or else, you can make your own. See here:
There's a recipe for Rift Valley cichlid salts, but use one-quarter to one-half the amount listed, since you want soft to moderately hard water for these fish; pH 7-7.5, 10-15 degrees dH would be ideal.>
Thanks again Neale!
<My pleasure.>
<Cheers, Neale.>

Please help - nitrates through the roof!! 5/18/09
Hi there,
We got a new 26 gallon (100 litre) about a month and a half ago.
<Six weeks old... should just about be cycled now, though still vulnerable to water quality swings, so go easy with stocking and feeding.>
We lost a few fish in the beginning, which was probably due to water quality and to a monster filter we had in the tank.
<Eh? Don't understand why a filter would cause bad water quality. Most water quality problems come down to [a] adding too many fish too quickly; [b] feeding the fish too much; and [c] not having sufficient water volume and filtration for the fish being kept.>
We currently have 1 golden Gourami,
<Males become very aggressive...>
1 dwarf Gourami,
<Worthless fish in my opinion; very prone to disease.>
2 Neons,
<Need to be kept in groups of at least 6, and prefers slightly cool conditions, around 24 C ideal.>
1 angel,
<You do realize Angels eat Neon tetras?>
4 penguins and 4 suckers (1 large and 3 small) in the tank.
<Suckers? Do you mean Pterygoplichthys species? These are FAR TOO large for this aquarium. If you mean Gyrinocheilus, then not only are these fish too large, they're also far too aggressive.>
I am feeding them flakes and blood worms at the moment.  I have read up about the whole cycling situation, but I just don't think I'm doing everything right.
<I'll say. You've obviously added too many fish too quickly.>
I have purchased a water testing kit. My ph is round about 7 and everything else seems okay, except my nitrite and nitrate levels (more than 250!!).
<I don't believe this number. For a start, which is it, nitrite or nitrate?  Next up, what are the units? The devil is in the detail! In any case, if you had 250 mg/l of either, your fish would be dead. So let's cut to the case here: anything other than 0 nitrite is dangerous, and will kill your fish. As for nitrate, levels under 20 mg/l are best, though up to 50 mg/l won't do much harm to your fish, except perhaps the Angelfish. Like most cichlids, Angelfish are intolerant of nitrate.>
They are through the roof and I'm not sure what to do!! I usually do 30% water changes on a weekly basis and have even tried doing them twice a
week, but it still won't come down.
<Too many fish, too quickly, and likely the filters aren't being maintained properly or stuffed with useless media (like carbon) instead of what you actually need, biological media.>
We have one corner filter, under-gravel filter and another hanging filter in the tank and they seem to be functioning fine. We have a castle and some pipes in the tank, and the fish like to play and hide in them and the suckers are very fond of them as well. We had some plants in the tank, I added plant fertilizer (as directed), but they turned yellow. I removed the plants yesterday and I'm hoping that it will maybe make a difference.
<It won't. Like the plants died because you either [a] bought plants that were cheap but actually aren't underwater plants (a very common con trick among retailers) or [b] your aquarium isn't suitable for plants: not enough light, the wrong substrate, etc. Undergravel filters, by the way, cannot be used with plants except floating plants or epiphytes (plants attached to wood or rocks).>
Firstly, please help me with the water!!???
<See above.>
Secondly, I am not sure about the amount of bloodworms to feed my fish. I am currently giving them 1 block per day, and flakes twice a day. Is that too much?
<I'll say. One meal a day is ample, and for this collection of fish, the smallest pinch of flake food is fine. Don't feed them at all while you
detect any ammonia or nitrite.>
I know I must check what they eat in 2-3 minutes,
<Too much...>
but that is very difficult, as my suckers don't always dine with the rest of the fish.
<Correct. Hence, you feed them at night, using algae wafers.>
Thirdly, my golden Gourami is looking a bit bloated, it has been like this for about two weeks and I've been reading up on it trying to find the
problem. I saw some people posting that it may just be bloated and I need to give it a deshelled frozen pea. Will that work or is the water causing
<Likely to some degree.>
I think the Gourami is female, but so is the dwarf (I think), so I'm not too sure if it can be pregnant.
It got a black spot in the middle of where it tail starts, is that normal?  I know the golden Gourami eats quite greedily when I feed them, but that is always the case. Can that be the problem?
<Likely environmental; concentrate on that for now.>
Please help me with this. I am quite new to the tropical fish scene and I just don't want to lose my precious babies just because I just don't know better.
<Much written for beginners here. Do have a read here:
Would recommend you take some/all of these fish back, and start adding a few hardy fish to start with, while you pick up the skills required. The Yellow Gourami is perhaps the toughest of the bunch, though males are super-aggressive and worth avoiding (males have longer dorsal fins than females). Space out each batch of new fish by 2-3 weeks. Use the smallest amounts of food you need; a piece of flake about the size of the fish's eye is really all it needs per day, and skipping a couple days a week if you have problems with water quality won't do the least harm.>
<Cheers, Neale.>

Re: please help - nitrates through the roof!! 05/19/09
Hi Neale,
Thanks for your previous response. I will check the links that you gave me and see if I can maybe get things on track. Unfortunately I left the water testing kit at home, but I will send you the exact readings tomorrow. I think it was the nitrates as one of our angels died quite suddenly last week.
<Hmm... nitrates don't normally kill Angelfish (or cichlids) quickly, but rather make them prone to disease, leading to gradually weakening health over a period of weeks or months. So I'd be looking at other, more immediate issues: ammonia, nitrite, toxins, etc.>
What I meant about the monster filter was, that it sucked in a few of our fish.
<Doesn't usually happen; fish are plenty strong enough to avoid being sucked into filters *of appropriate size* for the aquarium in question. So assuming the turnover isn't, say, 10 times the volume of the tank (in your case, 200 gallons per hour for a 20 gallon tank) there's very little chance the filter killed your fish. What often happens is a fish are weakened/killed by something the aquarist has (or hasn't) done, and the moribund/dead fish gets sucked into the filter.>
My golden Gourami was very aggressive with the dwarf in the beginning, but they are best of friends now. The purchase of the Neons was a mistake on my part. I bought them without reading up on them. I initially bought 7, but 1 died and 4 were eaten. Now there are only 2 lonely Neons in the tank.
<Who ate the other 4?>
The people at the fish shop was quite clueless and never told us much about the dwarf Gourami, he seems to be doing just fine at the moment. We have 4 Pterygoplichthys' (see picture as example). I am quite aware of how big they get. But we just love them to bits. They are great fish and we will look after them properly.
<Do understand you'll need 55 gallons, minimum, for one of this species, and 3-4 times that for 4 specimens. They also need massive filtration, upwards of 8 times the volume of the tank per hour. Do understand also that they are aggressive towards one another, and the dominant fish will kill the others if they can't avoid him.>
The big one is about 6 inches (15cm) and the other 3 are about 2 to 3 inches(7cm).We are moving into a new house at the end of the month and will be looking to get another aquarium later on. I will rehouse 2 of the suckers to that one.
When we bought the filters, the guy at the shop gave us carbon to put in the filters. What should we be using instead?
<More biological and mechanical media: ceramic noodles or sponges, as you prefer.>
Thanks for the tip about the plant. I'm not sure what plants they were, but no one told us that you can't keep them with an underground filter.
<Most any book about aquarium plants will state this. I'd recommend "Aquarium Plants (Mini Encyclopedia Series for Aquarium Hobbyists)" as being cheap, easy to read, and very useful. It's so easy to waste all kinds of money on plants, that spending some money on a book really is good value.>
I don't have algae wafers at the moment, will try to get to the shop as soon as possible. At the moment I am just feeding them bloodworms. Is there anything else that I can feed them?
<Algae wafers, courgette (zucchini), sweet potato and small pieces of seafood make good staples for Pterygoplichthys; for the midwater fish, frozen bloodworms (wet, rather than freeze-dried are better and better value) and other small invertebrates, augmented with quality flake and pellets is fine.>
When we got the tank, they gave us some hardy fish(according to them). It included the golden Gourami, some other small yellow fish, the big sucker and a Bala shark. But the Bala shark died in the 3rd week.
<Demanding, schooling fish; Bob's written about these at length here, do read:
http://www.wetwebmedia.com/FWSubWebindex/bala_sharks.htm >
When we lifted up the castle, he had died in there. Is it possible that he couldn't get out or do you think it was something else. He didn't have any markings on him. Then
a week later, we got 2 ghosts and 2 small Bala sharks. The ghosts were doing fine, but then they got sucked into our monster filter along with the 2 Balas. We were told to put some mesh in front of the filter to avoid this. The Neons seem to be fine though, none of them got sucked in?!
<Quite. Fish aren't sucked into filters when healthy.>
I know we introduced too many fish too quickly, but I really don't want to return any of the fish. They are like part of the family now and I will try my damndest to save all of them.
Thanks for the assistance. Will send the water readings tomorrow, should give you much more of an idea of what is going on in our aquarium.
<Cheers, Neale.>

Nitrate concentration in crayfish tank -- 06/28/08 Hi,= I have a problem with the nitrate level in my crayfish tank which I hope you can help with. It's only a small tank, just under 10 gallons, with an undergravel filter and another small internal foam- filter. It has been set up for over three months, and my crayfish (the only occupant) has been in it for two weeks- less than that. Since I added her, my nitrite and nitrate readings have always been 0. For the last couple of weeks, my nitrate level has jumped to 25 mg/L (nitrite still 0) and I cannot get it down. I know this is not high for fish, but am concerned that it may be too high for her as a crustacean. I have always done 25% water changes each week. The last couple of weeks, I did two 10% changes the first week, and then, as the nitrate level didn't decrease, a 50% change about 5 days ago. It doesn't seem to have any effect. I tested the nitrates of the tap water, after conditioning, and this was 0. I suspect its the amount of food that she loses when feeding (miniscule bits of fish seem to 'cloud' off while she chomps) and I do have some brown scum/algae which accumulates at the front, which I keep having to scrub off. I can't understand why the water changes are having no effect. I don't know whether doing any more just yet is a good idea as I don't want to start the tank off cycling again. Have you any suggestions? Should I be worried about this concentration? Thanks very much for your time. I couldn't find anyone else with this query for crayfish tanks. Best wishes, Kathryn <Hi Kathryn. Nitrate can be difficult to manage. The first thing is to establish the nitrate level in your tap water, which you have done. If you're finding that the tap water has 0 mg/l nitrate but the aquarium has 25 mg/l after one week, you almost certainly have an overstocked or overfed aquarium. Given that nitrite and ammonia are zero, the filter itself is doing its job just fine. Your crayfish isn't in any immediate danger -- the common swamp-dwelling crayfish sold as pets have evolved to live in a variety of water conditions, and will adapt to relatively high levels of nitrate without problems. Given the crayfish are primarily herbivores in the wild, you could opt to focus the diet on plant matter. There is less protein in plant material, and while your crayfish will still receive all the nutrition it needs, the amount of ammonia dumped in the water, and consequently the nitrate produced by the filter, will be far less. Across the week you might feed your pet on 5 days with plant material, and 2 days with something meaty. Beyond that, more frequent water changes will dilute the nitrate, and the use of fast-growing floating plants under bright illumination will further use up nitrate. Hope this helps, Neale.>

Re: Nitrate concentration in crayfish tank -- 06/29/08 Hi, Thank you very much for your advice- I will certainly try to shift her to a more vegetarian diet and find some floating plants. Hopefully she won't be able to catch and destroy them like she does everything else! Thanks for your time, Kathryn <Glad to help. Try soft plant foods like tinned peas and cooked rice as staples. The peas are great for protein, and the rice provides starch. You can also offer Sushi Nori, cucumber, courgette (zucchini), cooked carrot, blanched lettuce or pretty much anything soft and/or green. There's no need to feed crayfish every day. Feed in small amounts, and at night if you want to minimise wastage (crayfish are nocturnal). Inexpensive pond plants like Elodea will do double duty as forage for the crayfish as well as nice decorations for the tank. Maybe once a week offer something meaty with either shell or bones in place. These provide the calcium required for successful moults. Frozen krill and/or lancefish (both available in aquarium stores) will do the trick here. Some aquarists recommend adding iodine drops to the crayfish aquarium. You can buy this stuff (inexpensively) at marine aquarium stores. It seems to help prevent one common problem with crayfish, namely "bad" moults, where the crayfish dies part-way through. Use as indicated on the bottle, though perhaps a half-dose would be ample for just one crayfish. Cheers, Neale.>

Excess nitrates problem, FW   11/1/07 Dear WWM, <Melissa,> I have/had a 5 gallon tank with two panda Corys, mechanical and biological filtration. <Hmm... 5 gallons too small for such fish, and really too small for any fish. The main problem is a lack of stability, so even if a 5 gallon tank is fine one day, by the next it can be a death zone. The bigger the tank, the slower such changes, and the more time you have to fix them. Experienced fishkeepers can usually run a 10 gallon tank safely enough, but for beginners there is no doubt in my mind a 20 gallon is the bare minimum for anything like a consistent chance of success.> Yesterday when I left my house, my fish were fine. One of my Corys was displaying some clouded eye a few days ago, but it seemed to be improving. The other Cory was unaffected. <Cloudy eyes don't tend to go away, and even if they do, they're really an indication of infectious agents in the water. In other words, this should be an alarm bell.> When I got home about seven hours later, there were these tiny worms in my tank. They are very small, ranging from about 2 to 10 mm long, almost translucent, and free-swimming. They resemble Planaria but are not white. I suspect them to be nematodes. <Quite possible. Nematodes such as these are harmless, and simply turn excess food you are giving your fish into more nematodes. Cut back the food, clean the tank more rigourously, and the nematode population will die back. Again, an alarm bell.> I have not added anything new to my tank recently. My java fern has also started yellowing suddenly for some reason, I don't know if this has anything to do with it. <Likely not; are you fertilising the water? Like any plant, Java fern relies on minerals such as iron and magnesium from the water. This is used up over time, so at least monthly you need to top up with plant fertiliser.> Plus, there are tiny white specks crawling on the inside of my tank walls. <Could be nematodes, planarians or even some sort of tiny crustacean such as Ostracods.> I also lost both Corys over the last 12 hours. <Sorry.> I suspect both the worms and the fish loss to be due to excess buildup of nitrates in my water. <Wrong. The nematodes and the nitrate levels (which you don't quite) are a product of poor aquarium care. Provided you don't give fish too much food, there should be no food for nematodes to turn into even more nematodes. Likewise, nitrate comes from food, not thin air. So if you have relatively high levels of nitrate compared with the water you put into the tank, this means you are adding too much food and/or not doing enough water changes. Bottom line, the nitrates and the nematodes were warnings about a systemic problem with the tank; without fixing that problem, you allowed the situation to become critical, resulting in dead fish.> However, I don't see how this could happen as I siphon thoroughly once a week along with 20-25% water changes. <Not enough. The smaller the tank, the more the water changes need to be. Minimum, 50% a week for this system.> I also underfeed. <Apparently not, or there wouldn't be any worms. Understand this: nematodes are animals. They eat stuff. They eat fish food. They can't survive on just water and gravel. So if the nematodes are multiplying, that can only mean there is "stuff" in there for them to eat and turn into baby nematodes.> Although I did a full siphon and water change two days ago, yesterday I was still able to siphon out a very large amount of dirt from my gravel. This included white and brown specks about 1 mm as well as microscopic specks that looked more like dust than anything. <Organic detritus. This is the stuff you need to remove with each water changes. In a bigger tank, this really isn't a problem, but in a small tank, organic decay can be critical, resulting in things like rapid pH drops.> Today, I siphoned again, and even though I siphoned yesterday and did a 40% water change, today after an hour of siphoning I was still able to stir up a significant amount of this dirt. <Bizarre. Let's review how the gravel should work. In a tank with an undergravel filter, you need around 5-8 cm of gravel, through which water is drawn. Each week you need to stir the gravel and siphon up the solid waste that accumulates there. In tanks without undergravel filters, you don't need a deep bed of gravel unless you have rooted plants. In your case, if the only plants you have are Java fern (which you NEVER stick in the gravel but attach to wood/rock) the gravel need only be 0.5-1 cm think. Enough to cover the glass but no more. This should be very easy to keep clean. In tanks with plants that have roots (Vallisneria, Amazon swords, etc.) the substrate needs to be much deeper, around 10 cm. Actively growing plants will largely keep the gravel clean by themselves, and to a degree use the organic wastes as a source of nutrients.> I am not sure what is causing this huge accumulation of waste in my gravel. No amount of siphoning seems to decrease this amount. <Put the filter in a bucket of aquarium water and leave it running, and then take apart the tank and give it a thorough clean. Return only so much gravel as you need to cover the glass.> Ammonia and nitrites are both at 0. What should I do? <Clean the tank, and review the basics of setting up and maintaining an aquarium. Once you're happy you have them covered, go get some more fish, but choose something more suitable for a 5 gallon tank, such as a Betta or perhaps a few shrimps and small gobies.> -Melissa <Cheers, Neale>

Re: Excess nitrates problem  11/1/07 Hi again, <Greetings!> I understand that 5 gallons is difficult to keep balanced. I'm preparing a 15 gallon now...don't have room for anything bigger. <Good. While 15 gallons is still on the small size, it's certainly much easier to maintain than a 5 gallon tank.> My java fern is rooted to a piece of wood. I also have a piece of driftwood on which I am keeping java moss. <Correct maintenance for both these plants. If placed in the substrate, they rot.> My gravel is about 3/4 of an inch deep. <Use less. In a tank without plants or an undergravel filter, you really only need enough to cover the glass. I prefer to use sand with Corydoras than gravel; you will immediately see changes in their behaviour as these catfish happily root about in a more natural way. Aquarium sand can be used, but non-calcareous smooth silver sand (silica sand) costs next to nothing and can be bought at any garden centre.> I will take the tank apart and clean it as suggested. Should I empty out all the water as well when I do this? <Yes. Of course, make sure the new water is dechlorinated and at roughly the right temperature for your fish, i.e., not too cold and not too hot. Corydoras panda (which I think you said you had) like water on the cool side: aim for 20-25C, but no higher and not substantially lower. Do keep the filter running in a bucket of aquarium water while you're cleaning the tank; otherwise, the bacteria will start dying, which is a Bad Thing.> Thanks for the help. -Melissa <Good luck, Neale>

Bad link on your site... and FW algae, nitrification issue   10/15/07 Hello Crew member, FYI, you have a nasty link on your site located at /diatomfltfaqs.htm. It is the 9th post from the top, titled ?Re: Diatom Filtration? and the link is <http://www/> http://www dot aquarium advice dot com/viewtopic dot php?t=3250. (link is retyped so to prevent you from accidentally clicking it) The link attempted to install the following 3 viruses: Exploit-MS06-014 (Virus), Exploit-CVE2006-3730 (Virus), and VBS/Psyme (Virus) in rapid succession. My virus software stopped the attack, but my system was frozen for several minutes. <Yikes... I see what you mean... Have removed this link. Thank you> While I am taking the time to write you, I might as well ask a question. I have spent many hours reading your site and have asked a few questions in the past as well, and I must say that you people are the bomb. <La bomba!> Currently, I have a green water situation that seems to go against standard logic. In a nut shell, the problem worsens each time I vacuum the gravel or clean the filter. Several months ago the problem was not green water, but rather cloudy water. If I left the tank to its own (if I neglected it), it would clear up, but nitrates would rise as well to the point that water changes would have little impact. <Mmm, you need/want more "filtration"... low/ hypoxic to no/ anoxic spaces...> It is then that I clean the filter and/or the gravel to slow down the production of and lower nitrates, but that causes the water to turn cloudy. I try to keep the nitrates below 10ppm, but when water changes will no longer keep the level below 20ppm is when I know I need to clean the filter and gravel. <Yes... a common situation> After purchasing 2 Plecos who do a wonderful job of cleaning the glass, gravel and décor of all visible algae, the problem of cloudy water became a problem of green water, and boy is the water green. Visibility in the tank is about 4 inches, and it has been that way for about 2 weeks now. I am at a loss. All water tests are currently and stay great with the exception of phosphates, which I have not tested because I use to use a phosphate buffer to control Ph so I knew the reading would be high. I have since quit using the Ph buffer and have let the Ph rise as a result. High or otherwise, phosphate levels have no impact on the cloudy/green water. I have read so many of your articles and FAQs that I feel like an expert on the subject, but something is amiss. More info; I can't keep plants because my silver dollars will eat them. My tank is 75 gallons. I have 4 silver dollars, 3 Corys, 2 bushy-nosed Plecos, and 1 blue ram. I wonder if I do not have enough fish to support the biology in the filter? Is that possible? When I had many more fish I didn't have this problem. I have an EHEIM Pro 2 canister filter running about 275GPH and it is full of bio balls that I am very careful to not tamper with. <Good> The tank has been running for about 3 years. I use RO water treated with RO right (2dGH) and baking soda (3dKH). Everything in the tank is plastic, or epoxy coated except 3 pieces of Malaysian drift wood. <This, these should help> No nitrites, no ammonia, Ph 7.6, (I prefer lower but cannot seem to keep it down without using phosphates), nitrates 5ppm at last check. I need to get to the root of the green water. I have had aquariums for over 30 years, but never has issues like this. I am trying to keep this short, so will cut it off here. If you need more info please let me know. Best Regards, Scott <Not to make too much of a simple/simplified response sans explanation, but the "answer" to the situation here is more fine substrate... like another inch or so of gravel... or the addition of ceramic ring, sintered glass media... for the bioballs. This will shift more of nitrogen cycling to/back to denitrification... Bob Fenner>

High Nitrates  8/27/08 Hi there Neale (?), <Hello Lisa,> Hope you are well. <Can't complain.> Could you please help me out? In my community tank, I've been reading high nitrate levels for the last few weeks. This tank is a 30 gallon hex, with 5 guppies, 1 black skirt tetra, 1 giant Danio, 1 zebra Danio, 2 Plecos, 2 bumblebee cats and 5 Corys (many bottom feeders I know! I LOVE them - they are such happy creatures). The change has come about in the last few weeks, as I have made an effort to feed the cats a few shrimp pellets and an algae wafer or two on a nightly basis - I've been doing reading on your site and I believe it was Fenner that recommends feeding the catfish "meaty foods" twice a day. (Oh and I did add the bumblebees to the tank about 2-3 weeks ago (Microglanis iheringi). <Define "high" nitrates. Anything from 50 mg/l downwards is fine, and even 100 mg/l is unlikely to cause problems.> I realize a high nitrate level is due to excessive food decay - correct? Nitrites and ammonia levels are 0. pH is on the high side - 7.6 (I usually keep it neutral at 7.0 - out of the tap it's 7.2). <Nitrate comes from the end of the biological filtration process. Ammonia (from the fish) goes to nitrite, and nitrite goes to nitrate. Water changes are used to dilute the nitrate. Since nitrate is (basically) non-toxic, there's no need in freshwater aquaria to worry about it most of the time. Things are different in marine aquaria, and to some extent in Rift Valley cichlid aquaria, but for standard community tropicals you can usually ignore nitrate. So long as you aren't grossly overstocked/overfeeding and you do the 50% water changes each week, it should stay at a safe level automatically.> I've been doing partial water changes 2-3 times per week to keep the levels down. <OK. But how *much* water per change? Aim for 50% a week, one way or another.> I'm running a Penn Plax canister filter with a capacity of 65 gallons (I realize it's turnover that's the important factor). I just ordered a large bubble wand to provide both additional aeration and get the waste and excess food up and into the filter intake. <Hmm. Not sure how the bubble wand will help here, but OK. Neale's golden rule for spending money is always buy another filter when you have spare cash. Everything else is niceties, but a filter is always money well spent. Even a cheap little internal box filter jammed into the corner and filled with ceramic media or filter wool will do more good than a dozen bubble wands.> I wanted to move one of the Plecos (5-6" in length) over to the Mbuna tank however that nasty Chinese Algae Eater is in there and I don't want him to latch onto him. <Hah! Plecs and CAEs usually coexist, and I've mixed them together myself. Does depend on the relative sizes of the fish, and how much cover the Plec has (it rough aquaria they tend to hide during the day and feed only at night). To some degree, CAE behaviour depends on diet: adults are more or less omnivorous rather than herbivorous, and should be provided with a mix of green vegetables as well as opened mussels, bits of prawn, and so on.> What do you recommend in this situation to get the nitrate levels down? <Tell me what the Nitrate value is first, and then I'll comment. If it's below 50 mg/l, don't worry about it. Also check you tap (faucet) water supply. London tap water for example has 50 mg/l anyway, so aquaria in London will have nitrate levels above that. Doesn't cause undue problems most of the time. Fish adapt to even sub-optimal conditions, and provided everything else is basically sound, nitrate is a relatively trivial issue.> As always, thank you!! <Not a problem.> Lisa in Natick, Mass. <Neale in Berkhamsted, Herts.> Re: High Nitrates -- 08/27/07 Thanks again Neale. <Hello Lisa,> As you say, I did note on the FAQ that nitrate problems refer mostly to marine aquariums. I do not want to take advantage of your service so I will always do the research before asking a question. I so appreciate this great service. And thank you for your patience. I can sense a bit of humor in your responses - I'm not sure you're rolling your eyes at my questions - but I'd say it's definitely a possibility! :-) <More than likely, yes...> My concern with the nitrates is the change in readings (although the fish are not displaying stress). I usually receive 5.0ppm ratings for all three tanks (I apologize for not providing a reading). However, in this particular tank I AM overfeeding hence receiving a reading in between 40-80ppm (brought down to 40 with 25% water changes a few times per week). I believe I've sufficiently run out of real estate concerning number of fish also. There's even waste lying on the substrate (Plecos). I will begin doing 50% changes regularly on the weekends. <Solid waste -- faeces -- really aren't a problem, especially not from Plecs, which are herbivores. While unsightly, faeces contains little by way of toxins. Fish dump their "toxic waste" across the gills and in the urine, as ammonia. Neither of these sources is visible. This is why biological filtration is so important. Turnover is also important. For standard tropical fish (guppies, barbs, etc.) you need a filter providing at least 4 times the volume of the tank in turnover per hour. For big fish, like Plecs and goldfish, 6 to 8 times turnover is in order. That's how you decide on whether or not you have enough filtration, though obviously nitrite test kits can be used to directly measure your success at managing the nitrogen cycle.> I must have sensed "Neale's Golden Rule" for subsequent to writing my note yesterday, I installed a powerhead with a filter cartridge for added filtration - I will add a bit of carbon and bio media too. <Skip the carbon, and double the biological media. Carbon provides a questionable service in a freshwater fish tank. But biological media is ALWAYS useful.> I changed the canister's filter media too (except for bio media). Bubble wands are for wimps - noted. :-) <It's not so much air stones and whatnot are for wimps, it's just they're not very good value in terms of what you get in return. The only time I use air in aquaria is for powering box filters or, on marine tanks, for skimmers. I just don't see much use for them otherwise. This isn't to say you should use them, and if money is no object, they certainly add a nice touch to the aquarium. But there are better ways to spend your money if you want sheer improvement in water quality.> I will stop loving my fish with food and resort to the old feeding routine supplemented with a shrimp pellet, algae wafer or fresh veggie once or twice a week although seeing those bumblebee cats scoop up a pellet at the speed of light and the Cory feeding frenzy is quite fascinating! <Indeed! You're talking to a catfish enthusiast, so no question, they're among the most fun fish in the hobby. Cichlids obviously win out when it comes to intelligence, but if you want "weirdness" (as Calvin & Hobbes might say) you gotta go with catfish.> The CAE came as "a gift" as part of the Mbuna package. He IS fun to watch - the Mbuna chase him around a bit but if this guy latches onto my Pleco there going to be hell to pay! <Agreed. I kept one in 200 gallon tank with Central American cichlids. Worked quite well. There was also a gibbiceps catfish in there, and they all seemed to get along fine.> The Pleco I'd like to move into the tank is about 5 inches long, the CAE is about 3 inches. <Sounds a reasonable gamble. I'd try it out and see what happens. The CAE couldn't kill the Plec in one day, so it should be apparent if one or other fish is being bullied long before there were problems.> I do not have sufficient hiding places for him as of yet in the Mbuna tank however I'm going to decorate the tank with a great deal of rock next weekend. <Plecs love terracotta flower pots, so providing hiding places shouldn't be hard. Perhaps I will move the Pleco in there once the aquascaping is complete. I'll place a bit of driftwood in there too as he really likes it. <It's more than "liking", they eat the stuff too. While common Plec species can't digest wood (only "Royal" Plecs, Panaque spp. can do that) they do seem to use wood as a source of dietary fibre, and it keeps them healthy.> Do Plecos "feel" crowded - am I stunting his growth in the 30 hex? <Quite possibly, yes. 30 US gallons is rather less than what I'd recommend for a common Plec. Even twice that wouldn't be exactly generous.> Maybe I should just leave him where he is? I know Plecos can get huge in the wild and even in captivity... <The standard Pterygoplichthys species get to around 40-50 cm in the wild, but there are other Plecs that get twice that size. I've seen photos of as-yet undescribed Loricariid catfish literally the size of a child. There's a great You Tube video of a *school* of wild Plecs in a Mexican lake, and it's quite something to see this huge mass of giant catfish scooting about like overgrown Corydoras. Sometimes, aquarists don't realise how different their fish behave in the wild.> Thank you Neale! <You're welcome, Neale>

Nitrate in freshwater Eclipse 12 system -- 08/11/07 I have written off to Drs. Foster and Smith and That Fish Place but only received the pat answers which did not help me at all. I've seen your threads so thought I'd try you all. <OK, Jeanine, fire away.> I have a Marineland Eclipse System 12, freshwater, that has been up since January. I do weekly 25% water changes and vacuum the sand bed which is about 2 inches deep. I run my tank light about 7 hours a day. A month ago, I began noticing some of the brownish/red colored algae growing both on tank ornaments and on the live plants and when I checked nitrates, they were around the 40 or more mark. <Right, you have a 12 US gallon tank, which isn't much at all. So by any standards you need to handle this tank extremely carefully if you want it to be stable. That said, nitrates at 40 mg/l are fine for most freshwater fish. Local water in London is around 50 mg/l right out the tap, and people keep fish with this stuff fine. Sure, there are some nitrate-intolerant fish, like Tanganyikan cichlids, but the basic stuff like Neons and guppies generally couldn't care less.> After doing reading and checking, I decided I had too many fish - 4 Cory cats and 5 dwarf neon rainbows, so I donated the rainbows to an LFS reducing the fish to only 4. <The 4 Corydoras would be fine, but the rainbows aren't "overstocking" the tank, but just the wrong fish for such a small aquarium. They're hyperactive creatures. I'd sooner go with Glowlights, Neons, and other inactive small tetras when working with small (lengthwise) tanks.> At the time, I had been feeding the fish daily, so I changed to every other day feeding so I am definitely NOT overfeeding. I feed frozen blood worms one day and also Hikari sinking wafer for catfish the next feeding. Oh, I also checked my phosphates and they are around 0. <Now, frozen foods are great, and bloodworms low in proteins (something like 5%, check the package) so far less polluting than the same quantity of flake. People often forget that it isn't how much food you put in the tank that matters, but how much *protein*. That's why you can stick a head of lettuce in an catfish tank and let them graze away for a week, and yet the impact on the nitrogenous waste levels will be minimal.> I did a massive 4 gallons at a time progressive water change sequence until I got the nitrates down below 5. I always make sure the carbon filter pad is clean (in tank water) and I even rinse out the BioWheel in tank water to remove excess buildup (if there is any). <I say this twice daily, but carbon pads are useless, or at least, don't do any of the things aquarists think they do. Carbon doesn't remove nitrate and carbon doesn't reduce water pollution. All carbon does is remove dissolved organics, and if you're doing 50% water changes weekly (as you should be) then there won't be any dissolved organics anyway. So throw out the carbon, and replace with more biological filter media, which *will* do something useful. Corydoras, by the way, love big water changes, especially if the new water is slightly colder than the old water. If you're lucky, they'll spawn!> Okay, so I've done everything I know to do so now that I've reduced the nitrates and am not overpopulated or overfeeding, surely the nitrates will not start going back up quickly. Well, within 3 days of doing the water change/vacuum, the nitrates were already back up to a good solid 5 ppm color so they are obviously rising. <Nitrates are good in some ways, because they show the biological filter is doing its job. Don't worry about them. As I said, 50 mg/l is harmless in most cases, and even 100 mg/l won't cause major problems.> I have read that BioWheels cause higher nitrates but that is the filter on the eclipse system and no one says much about freshwater nitrates and BioWheels in their articles. <All sounds like rubbish. No filter can "make" more nitrates than another. Assuming you have biological filtration equal to the loading of the tank, each milligram of protein the fish eat will end up as exactly the same amount of nitrate, whether you are using a sponge filter, and undergravel filter, or a trickle filter. The only factors that moderate this are plant/algal growth (these use up nitrate) and denitrification in anaerobic sediments (where nitrate is broken to nitrogen). This latter is uncommon in freshwater tanks.> I want to keep the nitrates at a lower level so the algae will not get a major foothold again. <Non sequitur. You can have 100 mg/l of nitrates and no algae. You can also have 5 mg/l nitrate and lots of algae. Algae is a problem where a tank is "unbalanced", that is, there is an excess of light (especially sunlight) but not enough plant growth. Algae will grow more quickly if there's lot of nitrate, yes, but even if there isn't, algae can grow pretty well too. Add some live plants that grow rapidly. Vallisneria, hornwort, Cabomba, and Elodea are all good. Make sure they have lots of light. Honestly, once established, you'll be down to scraping algae once a month, if that. It's pretty amazing really. The mechanism isn't clear scientifically, but allelopathy may be a factor. Slow growing live plants, like Cryptocorynes, Java moss, Java ferns, Anubias, etc have no effect at all, by the way.> How can I keep the nitrates lower - I will continue my tank maintenance and weekly 25% water changes, but I don't want to have to continue these huge progressive water changes every week to lower the nitrates. <Forget about it. Too much work, not enough reward. Weekly 25% water changes aren't "huge" by the way, they stingy. 50% weekly is widely accepted nowadays to be a good baseline. The old idea that "old water" was somehow better for the fish has been thoroughly discredited.> I find it hard to believe that 4 Cory cats with live plants and no over-feeding and regular weekly tank maintenance still generates such a quick nitrate rise. My only thought is that it must be the BioWheel, but I'm not sure at all and don't know what to do about it. <You're fine with the fish you have. Add half a dozen or so small, inactive tetras like Neons, and maybe a handful of algae-eating shrimps for fun, and you'll have a nice little tank. Algae isn't the enemy by the way. If your fish breed, it becomes live food, and shrimps especially seem to eat nothing but algae and the microbes living amongst it. Algae is part of the natural world, and the only places you don't want it are the front glass and on the leaves of the plants. Everywhere else...? Get over it. Let the algae do it's thing. It's fish/shrimp food of the best sort and a valuable source of vitamins for them. Most fish will peck away at it occasionally, like cats nibbling on grass. But seriously, once you have rapid plant growth, the algae becomes a trivial issue.> Thanks so much, Jeanine <You're welcome, Neale>

Re: nitrate in freshwater Eclipse 12 system -- 08/11/07 Neale, What an AWESOME response. Thank you for taking time to respond so thoroughly. Yours is the first real answer I've gotten from anyone. I really don't see algae as the 'enemy', but obviously didn't want it overtaking the tank and plants and things. I will get some of the plants you recommended and see if that takes care of things. I have about 6 plants in there now, but don't think any of them are what you recommended. <Do some reading on "aquarium plants", "allelopathy", and "algae" and you'll get lots of information about how people think the system works, what plants work best, and so on. It's controversial, but I'm sold. When I tried it, it worked.> If I do get a few Neons as you suggested, is there any particular brand of flake food (which I assume they eat) that is not too high in protein? I have the Hikari micro pellets if they would work. <Should be fine. The secret to feeding fish is variety. Don't buy big tubs, but small tubs of flake or pellets, so you can regularly skip between brands. Algae-based flake foods are probably the best diet for most small fish. Some days, don't feed your fish any flake foods, but instead put in something like a thin slice of cucumber, some sushi Nori, or an algae pellet. Frozen foods are always good, but live daphnia or whatever are best of all. Raid the kitchen: bits of raw prawn or fish meat are often enjoyed by small fish. All sorts of greens can be pressed into service. As with anything in life, a little of everything is better than just one thing, however good.> Thank you again, I am really grateful, Jeanine <You're welcome, Neale>

Nitrates and Green Water   6/10/07 Hello! <<Hello, Vicki. Tom here.>> I've been reading through your FAQs on green water, since my tank has a sudden and terrible case of it. All of the responses stress the importance of testing the nitrate and ammonia levels in the tank. My question is this - is there any way to lower ammonia or nitrate levels without increasing the number of water changes? I'm worried that if I change the water any more frequently, I'll destroy the beneficial bacteria and have to cycle the tank over again. <<Vicki, provided the water changes are performed correctly, there's little chance that these will harm your bio-colonies which are housed primarily in the filter media. That said, you can also change your water too frequently which might seem at odds with what your research has turned up. We'll take this up later in your post but for the time being, think in terms of the quantity of water changed versus the frequency of the changes.>> Here's a little background: I have a 10 gallon freshwater tank with 4 mollies, 2 guppies, 3 tetras, a Kuhli loach, a horsehead loach, a Corydoras catfish, and a snail. <<Off the subject just a bit, Vicki, but your ten-gallon tank is over-crowded with incompatible species. For example, Mollies prefer hard, alkaline water (consider these to be brackish water fish) while Guppies prefer soft, acidic water. Same goes for your Loaches. As an aside here, Corys are highly social little critters that really do best in groups, not alone.>> The PH is stable at 6.9 and the temperature is 78. <<This isn't too bad for any except for the Mollies.>> Up until three weeks ago, I had a goldfish instead of the mollies. He died, I replaced him with the mollies, and within a week, the water was cloudy and green. <<Skip Goldfish until you're in a position to get a much larger tank, 30 gallons or better.>> First, I tried reducing the lighting (the lights are now on about 1 hour/day). <<An appropriate move here, Vicki.>> Then I tried adding about a tablespoon of aquarium salt (replacing it proportionally after water changes). <<The correct methodology but unnecessary. The Cory, Guppies and Loaches don't appreciate salt in their water and, under different circumstances, the proper salt to use for Mollies is Marine salt, not aquarium salt.>> I also added plants - I now have four of them. <<Good move for several reasons.>> When none of that worked, I tried taping a piece of water to the outside of the tank on one side, to reduce the small amount of sunlight that comes in. For the past two weeks, I have been doing 20% water changes every two days. <<Let's pick up on this once again. The green water you're experiencing is the result of an algae 'bloom' likely caused by an excess of nitrates and/or ammonium in the water. (The reason for testing for nitrates is pretty straightforward since these are largely responsible for the nutrients needed for plants/algae to thrive. Checking for ammonia/ammonium may be a little less obvious but ammonia (NH3) exists as ammonium (NH4) at lower pH levels. This is also somewhat temperature-dependent but pH is the bigger factor here. Since ammonium is also used by plants and algae -- in some cases before nitrates are -- this explains why this test is also important.) You've got a lot of life going on in a small environment which contributes to a proportionate amount of waste from the fish and, potentially, uneaten food. In a stable tank, a 20% water change once a week, or even two weeks, would be sufficient. In your case, however, I would recommend a single, 'massive' water change as opposed to multiple, smaller changes. My rationale is that a 20% change still leaves ~80% of the suspended algae and nutrients behind. These increase rapidly over a couple of days and you're back at 'square one', i.e. the reason why the smaller changes aren't really correcting the problem. One massive change on the order of 80%-90% will dramatically reduce both the algae and nutrients and allow your other measures to take hold and combat the algae growth.>> I've changed the filter cartridge once, but left the plastic sponge in, which is supposed to house some of the beneficial bacteria. <<You haven't specified the size of your filter, Vicki, but it's possible/probable that it's smaller than what is needed based on your stocking levels. Good for you, however, that you left the sponge in place. This is where the lion's share of the bacteria reside.>> I've also thoroughly vacuumed the substrate. I used to have a small amount of algae on the tank decorations and glass, but this has all died while the green water problem continues to flourish. <<Part of your plan is obviously working, Vicki. We just need to get rid of the suspended stuff.>> I admit, I haven't purchased a nitrate or ammonia test kit, yet. They seem fairly expensive and I'm not sure how the nitrates or ammonia could be high after all the water changes I've done. <<You don't need to start with an entire test kit if it's not in the budget right now. Individual kits for ammonia and nitrates, alone, can be purchased from virtually any LFS in your area. It's a good bet that you could find these even cheaper online. As for how these compounds could still be high, simply put, you have more going in than coming out. Algae is exceptionally prolific and you've got plenty of sources of nutrition in your tank right now.>> If the levels do prove to be high, should I change out even more of the water? <<Yes, but by quantity, not frequency.>> Won't that kill off the beneficial bacteria and cause my tank to re-cycle? <<Not to any significant degree. Fish rid their body systems of ammonia through specialized membranes in their gills, not through their waste. In other words, your fish will be providing the bacteria with a pretty steady supply of ammonia even after a large water change.>> Thanks very much for your help! - Vicki <<Happy to do so, Vicki. You may want to re-evaluate the size of your filter, as I mentioned. Within the realm of common sense, of course, it would be pretty hard to over-filter your aquarium as you currently have it set up. Best of luck to you. Tom>>

Nitrite And Ammonia Problems In A Big Tank   12/21/06 I adopted a 150 tall FW tank with a sand bed, two bio-wheel filters, one canister filter, several pieces of driftwood. Living in it our 4 grown Severums, 2 grown Jurupari, 1 2.5ft fire eel, 3 African clawed frogs, 1 small Knifefish, 1 Pleco, and 2 3 to 4 inch eels. I have had it running for about 3 months.  It seemed to cycle the first week I had it (even though we moved it entirely and saved all the media)  - with nitrites and ammonia levels going to 0 after numerous days of massive water changes My problem is that about every 10 days the nitrites and ammonia test heavy again. I repeat several days of massive water changes and it returns to a clean state. But without fail about 10 days later it goes off the charts. A local fish guy suggested that the sand bed is responsible. I took about 1/2 the sand out - from 3 inches to about 1.5. but it did not stay clean. I have also put ammonia rocks into all the filters - but they have never "turned green" which I was told means my ammonia test kit is giving me a false positive. I am willing to replace the sand with gravel and even install UGF is necessary - both ideas have been suggested. I do not overfeed. There are no dead fish. There is ample biological media in both wheels and in added media in all filters. Any ideas? Does sand in a FW present problems. I have 12 other tanks and everyone is cycled and stays that way. Thanks Tim < Do a 50% water change, vacuum the gravel and clean all the filters. Chemical waste levels should be down to zero. Feed as you normally do and test the water daily. I think you will find a logarithmic but gradual increase in these levels over a few days before they peak. The Bio-Wheels are great little inventions and you are correct that they should be handling all the bioload for this tank. The problem is in the canister filter. Food/waste gets trapped in the canister filter and there is very little oxygen in the canister for the bacteria to live on and break down the waste. So now the fish are generating biological waste and so is the crap in canister filter. The outflow of the canister filter has no measurable oxygen so bacteria cannot live and break down the waste. I would recommend that you add a bio wheel attachment to the canister filter outflow before it goes back into the tank and that you vacuum the gravel every time you do a water change. If the driftwood is not suitable for the aquarium then it could be rotting and contributing to the problem.-Chuck> Re: nitrates & ammonia in well water ... Ammonias Converting to Nitrates  - 05/19/2006 Thanks Chuck. What I'm trying to say is...Will putting water that has measurable ammonia levels in an established, cycled aquarium cause a spike in nitrates? < Yes.> All I know is that when I do a 25% water change on my 75 gal freshwater. The water clouds up within 18 hrs. and the nitrates start shooting back up. Like stocking a new tank too quickly. I think I should try to remove the ammonia before using. Do you agree? < Absolutely. Ammonia is very deadly to fish. Converting it to nitrates is a very good idea.-Chuck> Thanks again...DR

I Have read that high nitrates can cause unwanted algae blooms...    4/9/06 <Can> I have a 37 gallon and a 10 gallon tank. In the 37 there is A huge goldfish, 1 Gourami, 4 platys, 2 Corys, 2 angelfish. <Goldfish are not good to keep with tropicals...> My nitrite is finally down to about 0 for about 3 months now but the problem is my nitrates. They are so high! <How high?> Same in my 10 gallon which has 7 zebra Danios and 6 neon tetras. I have no clue how to get my nitrates down. <... Please read here: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm and the linked files above> I do excessive water changes - about 20% every weekend. I have been at this forever and they are still really high! I read that plants may use nitrates for something (can't remember what) so I added some potted plants (in little yogurt containers with soil and rocks on top) and they are actually growing little roots! <Good... takes a while> I added them into my 10 gallon tank so I could experiment because it is easier to take care of the plants because the tank is small and I can easily move things around. Also, the 10 gallon is shallow so I don't think I need exact and strong lighting because the light is so close and so strong for a 10 gallon tank, right? <Mmm, not necessarily> I have just some 15 watt regular white bulbs that my LPS sold to me. These are my first MAJOR tanks, I had little things when I was little, now I'm 15. My mom has a successful 250 gallon pond in our backyard and I understand that algae is natural, but I have the ugly brown stuff when she has nice green fluffy stuff. Should I add more plants because on one of the FAQ sites of yours I read that plants use about the same nutrients as algae. <Possibly... read> I also read the brown stuff will go away on it's own but it has been about 4 months since it has come... I set the 37 tank in the end of December. How long will it take for this stuff to as you said "go away on it's own?" <Maybe never> Will more plants reduce the time? <Likely so> The plants also look really nice when they are alive! I always went to PetSmart and got plants and brought them home and put them in my like 1 gallon bowl for my fish when i was like 6 and they always died! If you could email me back that would be great -  this is the first time i have used your site so I do not know I you post my question and your answer and I have to go searching for it. Thanks! - Marc <Read my young friend. Bob Fenner>

My poor harlequin is breathing from the surface!? Inherent BiOrb limitations, problems   - 03/26/2006 Dear WWM, <Molly> I am having some trouble with my relatively young tank. It has been up and running for about 3 months now (not including the pre-fish cycling period). It is a BiUbe. <BiOrb? Akin... a circular tube rather than an oval> I have 6 x harlequin Rasboras, 1 x male Betta splendens, 2 x smallish bottom feeders. I have followed all the instructions on setting up a tank religiously and all my readings are always perfect -except for nitrate (NO3) which always seems quite high -have been doing water changes to bring it down (is coming down slowly). It's in the 50-70 range which my test kit says is bad but not toxic. Is this right? <Not correct. Please read here: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm and the linked files above> Everyone seems happy and fine although the tank gets dirty VERY quickly. <These units have this trend/trait... unfortunately "kill off" much livestock and hobbyists consequently...> I clean the top of the filter tube and the rock I have when I do water changes but they, and my plants (not live) become grubby very quickly -a few days tops. It is a green sludge, sometimes brown.   Is this algae? <A mix of this and bacteria mainly> Why is it becoming so dirty so quickly? <Inadequate filtration, circulation... the unit itself> Should I change the filter? Or am I feeding too much (once a day a pinch of flakes which all get eaten up)? <Both changes would likely help> -Perhaps I should also mention that during my pre-fish cycling period I put in some live plants but they   kept going brown and dying so I only have plastic now. Any ideas why? <All sorts... posted on WWM> However, this evening I noticed that one of my harlequins seems to be breathing from the surface. He goes up for air for about 10-20   seconds, swims around for a few seconds then goes back for more. No one else is behaving oddly. I am very worried for him. What could it be? <Lack of oxygen, pollution... see WWM re... real trouble once again with this product> My temp is 78-80. Many thanks for your wonderful website, Molly, London. <Please use/read it... and soon. Bob Fenner>

High nitrate and cloudiness... amphibian system   2/9/06 Hello I desperately need your help. <Really?> I have a 60 gallon tank with about 20 gallons in it. It has been running for 6 years. The past few months I have had cloudy water and nitrate levels over 160. <... yikes> I have done several water and filter media changes and lots of vacuuming and even taken some rocks out of my tank. I added plants and even tried leaving it alone for a while.  All I have in my tank is one fire bellied newt. pond stone. very little gravel. some plants. and two glass fixtures and two rocks that gave always been in there. no matter what I do the water does not clear up and the nitrates do not go down. I have a Fluval 2 plus underwater filter. I have tried all different kinds of media for this and  nothing helps. <... unusual...> I feed my newt live Blackworms/bloodworms. I was curious if I should add an air bubble thing. Or maybe different plants or some sort of gravel under the pond stone. <Does need a filter of some sort...> Or take everything out. Please help! I have been all over your web-site and tried some of your suggestions but nothing seems to work. I have checked the water and other than the nitrates its all right. the tap water I use has a ph of 7.6 but the tank is 7.2      They treat the water with chlorine and chloramine. I use Amquel. Some cycle. and some metal remover. please let me know what I should take out or add. Also whether I should restrict sunlight or my tank light or expose it too more. please help. I know you guys don't specialize in newt tanks but all the other sites have been no help. And your site is the best. Thank you very much  Jason <... First, I would check your checker... your test kit may be off... Next, I would start changing more of the water more frequently... at least a quarter every week, while vacuuming the bottom. Do please give specifics re the media tried... And lastly, if it is just the newts you have, are concerned with, I would not be overly concerned with nitrate per se. Bob Fenner>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: