reducing nitrite

I have a 40 gal tank that's been set up for about 10days. I've moved my 4 orandas into it, from their 25 gal, using the same water, same gravel and same filter. However, whilst PH is fine (7.0) ammonia is nil, nitrite is .25. This is the first time it's ever been higher than 0. If I don't feed for a couple of days, will it drop naturally?

You are in mid cycle. If you don't know what the cycle is then Google for it. Nitrite levels will eventually fall away provided you have a big enough and functioning filter running. The issue in the meantime is managing the levels to be safe enough for your fish. It may take a couple of weeks before your bio-filter is properly re-established. DId you wash the gravel/filter in tap water? If you did you probably killed the bio filter.

Not feeding will help somewhat, but the fish will still excrete waste even with a few days of fasting. Feeding less to minimize the amount of food that doesn't get eaten is another choice. The main danger with nitrites is if it is absorbed, it can bind to hemoglobin and make hemoglobin unable to transport oxygen. Thus the fish will appear to be gasping and generally in respiratory distress even if the water has plenty of oxygen. It's like suffocating from the inside. You can minimize the impact of the nitrites on the fish by adding a little salt (sodium chloride) to the tank. The chloride ions compete with the nitrite for uptake across the gills. It doesn't take much salt to give the chlorides an 'upper hand' so that the nitrite uptake by the fish is minimized. There's an exact formula but an approximate sufficient dosage would be a teaspoon to a tablespoon (total) of rock salt (sodium chloride with no additives found at the grocery store commonly for homemade icecream machines, same as 'aquarium salt' from the pet store, much cheaper).

The new tank is under going a mini spike. Likely due to a small die off of your bacterial colonie. Ammonia level 0, nitrites .25 - nothing to worry about.

It will drop naturally wheather you feed or not........ Frank

On 2004-12-09, fishyfodder <djhatukpcdotnet> wrote:

Not feeding for a few days will help. What you are seeing is the phase during cycling where the bacteria that convert ammonia to nitrite have grown to the point where they are quite good at getting rid of the ammonia and producing nitrite, but the bacteria that convert nitrite to nitrate haven't fully established themselves yet because, up to this point, there wasn't much nitrite for them to eat. The result is that you have excess nitrite until the nitrite-eating bacteria catch up.

If you just leave the tank alone, nitrite levels will eventually drop by themselves and, in another few days, you will measure zero ammonia and nitrite, and you'll see nitrate levels rising gradually. (The nitrate is eventually removed by anaerobic bacteria too, but that process is too slow in most tanks, unless the fish load is very small. We get rid of the nitrate by doing water changes.) But, in the mean time, nitrite levels might get high enough to endanger your fish