Chemical Question

[Eraserhead]

Hi guys,

In general, how does the toxicity of Nitrite (NO2) compare to the toxicity of ammonia? Also, I know that adult cichlids, in general, are more resistant to ammonia toxicity than zome other fish (ie puffers), but does this include fry? I had 5 fry in a breeding box in my main tank, and then set up a little tank for them. I used gravel from my established tank, and there was never any ammonia in the tank. But one died today, and I noticed that the other were breathing very heavily (there was also a fairly strong current in the tank). I moved them back into their old breeding box, and two more sort of died in transit (a whopping 25 feet away). I took a reading and there was 0 ammonia, but a small amount of nitrite (around .25ppm). Could this have done it? The remaining fry are pretty hard of breathing. I have another small breeding box in the tank that holds a different batch of fry (there are 9 of them), and they are all just fine. Never had any problems with the other fry in the big tank.

Just wondering,

Thanks!

Bobby

[JustOneMore20]

Nitrite is the most toxic to fish. 0.25ppm isnt alot, but fry are more sensitive to water conditions than adults, so that could have been the cause of death and the cause of them breathing heavy.

Was the temp or pH any different in the tank you setup?

[emc7]

It sounds like your fry tank had a mini-cycle and your test caught the tail end. the ammonia and nitrite were probably much higher for a brief time. Once they are both 0, you should be able to put fry back in it.

[Eraserhead]

Originally Posted by emc7

It sounds like your fry tank had a mini-cycle and your test caught the tail end. the ammonia and nitrite were probably much higher for a brief time. Once they are both 0, you should be able to put fry back in it.

Thanks for all the info. The temperature was the same for both tanks, I think it was just the nitrite toxicity. My main tank is constantly between 78-80 degrees, and I had a small heater in the little fry tank to keep it about the same. I cant get my main tank to go any lower than that, it seems to maintain about that temperature with the heater turned all the way down. Kinda of a warm house The survivors are all acting more normally now that they are back in the big tank. I'll probably wait a while and put them back in their little grow out spot when the coast is clear. In the mean time, would it be okay to put a small amount of pure ammonia in the tank, and then take frequent readings to be sure it is all being quickly processed?

Thanks!!