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High Nitrites?

2385 Views 9 Replies 5 Participants Last post by  dwalstad
Which of these things, or would all of these things, cause high nitrites in a classic 20g el natural set up? A large drop of guppy fry, higher than normal temperature, and/or more food than normal. I don't have a testing kit - but the fish were showing signs of nitrite poisoning yesterday so I did a 15% water change but one of them died overnight. I had to do a 50% water change to save the rest of the fish, which all seem to be acting more normally now. I also did a semi-vacuum of the substrate. In the future is there anything I could do to help reduce the nitrites or prevent this kind of a spike? Should I do a further water change?
R.I.P. to my dearly departed SAE.
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What symptoms did you notice in your fish? I don't think there is anything very specific to nitrite poisoning that isn't also a symptom of other things, so there is no way to tell, without testing the water, whether nitrite is the poisoning.

Assuming the problem is nitrite, more food than normal might cause it, if there is enough bacteria in the tank to convert ammonia to nitrite. There would probably also be an ammonia spike at around the same time. I doubt the guppy fry would make much of a difference - they are too small. But if you have so many guppies that you can't count them (like mine!), having a dead fish or three in the water decaying would degrade the water quality - could have been part of the problem.

High temperature would cause the water to have less dissolved oxygen, which could give the fish difficulty breathing, a classic symptom of nitrite poisoning. So while the high temp doesn't, as far as I know, affect the nitrite directly, it could certainly cause similar symptoms.

My suggestions: buy test kits for at the least ammonia and nitrite. There is no excuse not to have these - if the nitrites were creeping up over time and you had been testing the water, your SAE might still be alive. At the least, they are the only way to eliminate two of the greatest fish killers (ammonia poisoning and nitrite poisoning) if you do have a problem, and they will give you early warning of any long-term buildup in ammonia or nitrite. Long term low-level poisoning can also kill fish without any symptoms obvious enough for you to realise what the problem is.

If the temperature in the tank is too high, try to lower it by allowing more evaporative cooling, switching the lights on for less time or at cooler times of the day, and, in an emergency, using frozen bottles of water to reduce the temperature temporarily. Also increase the aeration in the tank to reduce the problems caused by low dissolved oxygen in warm water.

Next time you suspect any kind of poisoning, do a much larger water change first off. 15% water change leaves 85% of the toxin still in the water. It hardly makes any difference to the fish. Small water changes are great, if done frequently, to keep a system stable, but if you are wanting to remove something bad from the water, large water changes are the fastest way to do it by far.

Without a test kit you can't tell if there is still any nitrite or ammonia in the water (or, in fact, whether there ever was any - the problem could have been something else with similar symptoms). I would do 50% daily water change on that tank until you have gotten test kits to confirm there is no nitrite or ammonia.

Good luck - I hope your fish stay well from now.
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I forgot to state the obvious earlier: if the problem is high nitrite, a little aquarium salt (or table salt, if you are desperate and have no fish-safe salt) will help to detoxify the nitrite. Salt reduces the degree to which the nitrite prevents the fish from carrying oxygen in their bloodstream, so they won't suffocate so easily if there is some salt in the water.

I wouldn't add much salt to a planted tank, though, unless you know the problem is high nitrite. Salt won't help fix problems with elevated ammonia, high temperature, or whatever else could cause similar symptoms.
Not nitrites - it was ammonia

Helen, Thanks for such a great reply. After I posted yesterday I went and got my water tested and got a kit. My tank has always been so constant and stable that I've previously only had to use my LFS's testing equipment. In these emergency cases though you really need your own. It turns out it was high ammonia - not nitrites. My fish were not displaying behavior that looked like ammonia poisoning. Perhaps because of the high temperature it really looked more like nitrite poisoning. All my fish are now back to normal. Even my kuhlis have gone back into hiding! I am going to test again and do another 30% water change if necessary this evening just to make sure that the levels are normal. I may also throw in a Giant Hygro - I'm told they are very good at taking up ammonia.

I have a Nerite snail that only breeds in the presence of salt, so adding salt isn't really an option. Although Nitrite wasn't the problem I'd be interested to know if there is anything else that would help neutralize nitrite?

Even evaporative cooling was not helping the heat problem - I had the top off and 2 fans going. I had to buy a second air conditioner to get things back to normal. It gets to tropical temperatures in Toronto out of nowhere and my central air was not picking up the slack. I'm now wondering if higher than normal heat could prevent the plants from taking up ammonia? I was feeding a little more than normal because I wanted to make sure the fry had regular feedings - but not enough for it to cause such a dramatic and quick change in ammonia levels. Also, I'm told that a fry drop even a large one usually doesn't have such a dramatic effect. Does anyone know if/why the heat could have caused this? Also, I think the short burst of extra ammonia has acted like a plant fertilizer. Since things have gotten back to normal almost ALL of my plants seem to have new shoots overnight. Even my Cabomba, which typically doesn't do very well in my tank, has shot up to the surface within 3 days with lots of thick leaf growth. Any ideas?
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Hi Rusalka,

I'm really glad you got a test kit. In my experience you can have ammonia or nitrite creeping up way before you notice altered behaviour in the fish. Fish are mostly prey animals, which means that they have evolved to not show any weakness, lest they be singled out and hunted down from the school. This means that they will be suffering (from illness, poisoning, whatever) for some time before their behaviour changes. So if you wait until you can see a problem in the fishes behaviour, the problem might have gone from minor to serious. I think water testing is really important to help prevent problems in any aquarium, and a situation like higher water temperatures can certainly tip a previously balanced tank out of balance.

You might like to find out how much salt your snail needs to breed in. It only takes a tiny bit to reduce the toxicity of nitrite. I don't know if other chemicals have the ssme effect - quite possibly, but whether there is anything as safe as salt I don't know.

I think that the high temperature could have contributed to the problem in three ways.

1. Ammonia is more toxic at higher temperatures (also at higher Ph).
2. At higher temperatures fishes metabolism runs faster. They would probably have been eating more, even if it was just more algae off the plants and glass. This would mean more waste in the water.
3. Higher temperatures mean less oxygen in the water. This makes the fish more easily effected by any other problems.

I would keep testing your ammonia and nitrite daily for at least several days. You could get another spike soon, especially if the weather stays hot.

I hope things stay good for you and your fish.
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I haven't tried this myself, but I've read about people making a home-made 'chiller' by putting a few ice cubes in a plastic bowl (that will float), with just enough cold water to just cover the bottom of the bowl. If it's short term and you're desperate... Just keep an eye on the temp.
Hey there I found out a bit more about my Nerite Snail. It turns out that they are the most prolific in brackish water - so no salt for me!! I wonder if Sodium Bicarbonate would have a similar effect on the Nitrite?

I'm still dealing with slightly high ammonia - it is really mystifying me! My tank is pretty heavily planted - I don't know how ammonia has a chance in there! Hopefully it will calm down in a couple of days and is still a byproduct of the high temps. I'm also worried about the massive water changes stressing out my fish. I added the Giant Hygro and overnight it's already growing! So I'm hoping that that will suck up any extra ammonia!

My guppies are acting normal - feeding, flirting, exploring, etc. and there are probably 40 fry still swimming around. But I have noticed some of my "teenage" 1 month old fry glancing off the filter and substrate - not very often, but it still worries me. With all the stress I'm not surprised - so far no ich or other signs of ill health have shown up. I'll be keeping an eye on it!
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1 teaspoon of sodium chloride per 20 gallons of water is the proper dose of salt for nitrite in the water. It is the chloride that competes to gross the gills, and keeps out the nitrite. (other sources of chloride would likely work)
The specific things to look for in fish that show nitrite poisoning is brown blood. (Nitrite poisoning is also called Brown Blood Disease- google it) This is often seen in outdoor ponds in the spring. The pond has been cold all winter, and the fish metabolism is very low, and the bacteria population also has not been very active. In the early spring the fish become more active faster than the bacteria can regrow. The ammonia removing bacteria do their job, so ammonia may or may not be a problem, (usually not) but the nitrite rises. The fish can be seen with a sort of odd brown discoloration in the thinner tissues (gills, fins).
The blood is not carrying oxygen very well, so the fish will likely be found piping (sipping or gulping air at the surface).

The dose of 1 tsp /20 gallons is so low that just about all plants, and all salt-sensitive fish will handle it without a problem for the duration of the problem. Just keep up the water changes until the cycle bacteria have caught up to the waste load.

Optimum conditions for raising fry are not exactly the same as maintaining the adult fish. I would suggest moving the expectant Mom to a nursery tank a week or so before the drop,(Use a cup, not a net so her pregnant belly is supported by water during the transfer) then raising the fry in this separate tank. I have found Java Moss to be very helpful: the microorganisms that live in the moss is just about the best fry food I have sound so far. You can also raise green water to feed them, and this is certainly nothing you want to add to your main tank! You can do as many water changes as you need to to keep the water chemistry optimum for the fry. The large mass of Java Moss will remove a fair amount of nitrogen, as well as feeding the babies a bit, so you will not need to feed quite so much as if you were raising them in a bare tank, and may not need to do quite as many water changes, either.

I have at times done some rather large water changes and my fish are fine. The secret is to match the water chemistry as closely as possible: TDS, GH, KH, pH and salinity.
With some sort of ongoing ammonia issue, I do not think that a single large water change is the solution, though. You might want to do twice as many regular water changes, and add an ammonia locking product (Most dechlors will lock up ammonia, read the label). Remember that some tests will still show ammonia, even if it is locked up.
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Ammonia gone!

Thanks to everyone who gave me such great advice and for sharing their expertise. My ammonia, nitrite, and ph are all completely back to normal today. The giant hygro is already shooting up and I added some curly salvinia to help with any toxin removal. I have not seen any of the guppies glancing today so perhaps they were just getting over the shock.

Here is a hasty shot of my tank as is, so you all know what you've been helping me with! I'll be moving the filter in the foreground to the opposite side of the tank once the hygro at the back of my tank has taken hold, so try to ignore it. Also, the salvinia is in "snail quarantine", so once it appears all clear i'll put that in and remove the duckweed. I'll take a proper 1st tank debut shot and post it soon. Thanks again!


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Re: Ammonia gone!

Nice tank. The plants look like they're off to a good start. Good going!
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