Nitrite Levels

[Arjuna]

I keep reading in online forums of people who have 2, 3 ppm (or even higher) Nitrites and their fish are still alive. Of course, they usually don't have GOLDFISH - but still - isn't that high?

I'm cycling a tank now and every time my Nitrite level even LOOKS like it's going to go to .5pmm - my fish start "scratching" themselves on stuff in the tank and gasping for air at the surface. I know my cycle might speed up if I let the Nitrites go a little higher - but I can't bear to see my fish uncomfortable, so I change their water out to give them some relief.

That said, what do y'all normallly recommend as an absolute HIGH LIMIT on Nitrites?

Another thing I've noticed. Seems that sometimes nominally high concentrations of BOTH Ammonia and Nitrites have a greater COMBINED negative affect on my fish. This might be something worth noting for beginners. The fish might be able to withstand .5ppm of Nitrite on it's own - or 1ppm of Ammonia on it's own. But the two combined simultaneously seem to have an exaggerated negative affect.

Anyone else notice this?

Take Care,
Mark

[AngelMom]

NitrItes should always be zero after the tank has cycled..........if it's not, there is a major problem in the tank. Long term exposure to either ammonia or nitrItes will kill fish. Even long term exposure to high levels of nitrAtes (80 ppm or more) has been shown in some studies to cause major health problems.

Because ammonia and nitrItes are both toxic to fish (though the nitrItes somewhat less toxic) it makes sense that the fish will be more uncomfortable with both present.

For your cycling process, it really depends on the fish. With a fully loaded tank during an inadvertent cycle (after using antibacterials) I had ammonia up to 4 ppm and then nitrItes up to 10 ppm at their peaks. Could possibly have done larger water changes (was doing 20-30% daily on a 60 gallon tank) but felt that the risk of pH crash or shock to the fish was higher than them having to deal with the nitrogen compounds. Basically, if the fish are in distress, then you must do what you can to help them.......and it sounds like you are.

[Buddha_Red]

what is the ideal fish to cycle with?

[AngelMom]

It really depends on what you want to keep in the tank. Gouramis, paradise fish and bettas are good as are mollies, platies, swordtails and a lot of the South American and African Cichlids. For the cold water fish, Comet (or "feeder") goldfish as well as fantails and black moors are good choices.

[Buddha_Red]

thanks a bunch!

good to know this, copying to my library of tips hehe

[Arjuna]

Diane / Budda,

Okay, idiot here - so don't yell to loud at me - but do let me know if I'm wrong here.

I have seen lots of lists of fish that are supposedly good fish to cycle with. And, I have seen lots of advice NOT to cycle with fancy goldfish because they can't tolerate cycling very well.

Well, since I'm on week 6 of my cycling (with goldfish) - I'm thinking that you can cycle with just about any fish - and do it safely. Here's why ...

As long as you are willing to do frequent water changes - you aren't going to kill any fish as a result of high ammonia or nitrites. Lately, I've been setting my threashold at .25ppm for both Nitrite and Ammonia. I change the water when either exceeds those limits. So the fish never get exposed to high amounts of either toxin.

A possible "hole" in my theory might be that some fish can't stand frequent large water changes the way my goldfish do.

I don't think that high levels of ammonia or nitrite help to cycle a tank quicker. I'm cycling another tank fishless using pure ammonia and I keep adding ammonia to keep it around 2ppm but I just don't see any accellerated nitrite to nitrate conversion. I think the bacteria that converts nitrite to nitrate MIGHT even be inhibited by high levels of ammonia in the tank.

Am I way off base here?

Take Care,
Mark

[AngelMom]

Theoretically, I suppose you could cycle with any fish IF you can keep the levels of ammonia and nitrIte low enough. In reality, it's not something I would want to try with sensitive fish, though sometimes we have no choice. I can tell you that I do believe that exposure of sensitive fish to all but trace levels of ammonia and/or nitrIte will compromise their immune system and eventually shorten their life.......I've had it happen more than once, just didn't realize many years ago that's what was going on. And yes, the hole is that most tropicals do not do well with water changes over about 30%.

It's good that you are keeping the levels so low.......it may take longer to cycle, but your fish will be better off for it. Hopefully you will not have any other problems with them!

I don't know about your suggestion on ammonia inhibiting nitrIte converting bacteria..........how long have you been adding the ammonia? You may not have hit the nitrIte spike yet. Generally, you will not see any nitrIte until after the ammonia spike, and likewise, no nitrAte until after the nitrIte spike. Someone (I think PhoenixShade) posted a chart in one of the forums that showed the relationship of the ammonia and nitrItes during the cycle. If you're curious enough, you might want do do a search on cycling threads.