How do I lower my nitrite levels?

Question

I have a new fish tank - I have had it nearly 1 month now. I started with 6 fish and I am now down to 3! They are all getting ill and dying on me! I have discovered it is because my nitrite levels are too high. I have bought a nitrazorb pouch and that has helped a little but nowhere near enough and I am doing daily water changes but none of this seem to be helping. Does anyone have any other suggestions?

Also, Is there anything else that could be making my fish ill? My ammonia and Nitrate levels are low so thats not the problem....

Answer 1

You don't say how big the tank is... When did you start doing the water changes? How much water do you change daily? (you may be changing too much now) Also, do you have a filter running in the tank? What kind of fish? Is the water cloudy, does it smell? Is there a heater? What temp do you keep the tank at? All this info is important to finding the cause of the problem. BTW, who told you it was the nitrite level that was killing your fish? That is usually not what kills fish in new tanks, it is the ammonia!

All three of those chemicals, ammonia, nitrite and nitrate are products of the nitrogen cycle in a new aquarium. Each one will spike (increase) and then drop as the tank goes through the complete cycle and the beneficial bacteria increase in numbers. Your fish may have died during the ammonia spike and not the nitrite spike which comes next.

As soon as the bacteria reach the optimum amount to metabolize the ammonia and nitrites, then the next spike will happen. The nitrates are still toxic to the fish, but not as bad as the nitrites and ammonia (the worst of the three). Live plants use the nitrates as food. (algae is included as a plant)

Depending on the size of the tank, it could take up to a month to complete the nitrogen cycle. Since you say it is the nitrites that are high, that means you are in the middle of the cycle and still need the secondary bacteria to multiply to the point where they can keep up with the ammonia production.

Ammonia is produced when fish waste and uneaten food decay. You may be feeding too much. Only feed once a day and only as much as they will eat in 3-4 minutes. If any is left floating on the surface after 4 minutes, you have fed too much. I even skip a day's feeding during each week. A hungry fish is a happy fish....

Weekly 25-30% water changes must be done as long as you have the tank up and running. Never change 100% of the water! You will remove all the beneficial bacteria and have to restart the nitrogen cycle from the very beginning.

Feel free to email me if you want to give me all that info and we can explore the problem further. Be sure you have entered your email address TWO times so that it is confirmed to the "answers" site and I will be able to email you back.

Good luck!

Answer 2

Very simple. Only 10% water change a week, if you have a sponge filter Never wash it out under the tap as this kills all the bacteria that convert nitrite into nitrare. Use the water you take out each week and just give the sponges a quick rinse through. If you are using an undergravel filter and your nitrites levels are still not dropping then you are over feeding. Most new people to the hobby overfeed. Use a good de-chlorinater when you top the tank back up. Fish waste is amonia which gets broken down into Nitrites by one type of bacteria, This in turn is broken down into Nitrates by a different bacteria, Nitrates are then used by plants. So as you can see its basically all down to filtering. Your local pet store will be able to sell you a liquid bacteria to boost your system. Good luck.

Answer 3

The above answer is pretty much spot on to be honest but the shortened version would be, that you lower nitrites by doing regular partial water changes in your tank. Depending on how how the nitrites are then 20 to 50% water changes 2- 5 times a week to start with.

Its called "new tank syndrome" and will hopefully settle down as your filter becomes more established. You will still need to do part water changes (10-20%) between every 1-4 weeks in an established tank though depending on how many fish you have in your tank.

Don't change the whole lot and please try and use water of the same temperature that has been de-chlorinated (you can buy drops from the shop or leave the water standing overnight to do this).

If this doesn't seem to work seek the advice of a good aquarist (most vets are useless on this subject, I know because I am one of the few vets with an interest in this area). Advice is usually free and they will be only too pleased to help someone who is trying to do it right.

Answer 4

Hi there - this is new tank problem and maybe a new fish keeper problem too - through inexperience you are changing too much water you may be harming the fish by altering the ph levels of the water too suddenly - fish cannot stand big changes in that way.Daily water changes are to much - if these fish are new to the tank they may have already been suffering from a change in ph and this can readily kill them.

It is always a good idea to test the ph of your tank and then to test the ph of the water in the bag with the fish in - if there is much of a difference the fish should be introduced to the tank over a period of a few days - if it is sudden it will kill them.
Best of luck - your tank will settle down - you will relax a little and all will be well - plant as many plants as you can in the tank - it will help it to mature.

It takes about 3 days for the alteration in ph to kill a fish - they go from healthy when bought to dyeing quite suddenly in 3 days.

Best wishes
Lynne
52 years of fish keeping experience

Answer 5

I believe you have this wrong the normal breakdown of fish waste is Ammonia to Nitrite then nitrite to Nitrate check your filter and clean it in water from your tank there is probably a build up of the nitrate

Answer 6

It sounds like your fish are not getting enough oxygen, nitrate levels go out of whack when water conditons are very poor, very dirty, is your filter working properly? Check that, also, daily water changes are not a good idea, check that your filter is working properly, increase oxygen levels, put conditioner in the water, and Cycle if you have it. How are your fish dying, more information is needed about that, Clean the filter, and do not change the water right now. The tank needs a chance to stabilize, and won't if you are doing that. Good luck.

Answer 7

By cycle your pet store will have it, its helpful bacteria. They also sell chemicals that detoxify ammonia and nitrates. Plants and watching how much you feed them will help a lot too.

Answer 8

Are you feeding them too much? Try feeding them brine shrimp and good quality fish food.

Answer 9

Check into plants!!!! The nitrates feed them.