# Nitrite spike in less than 24 hours in established tank.



## dandries (Apr 6, 2013)

I have a 60 gallon tank that has been set up for at least a year. It has to plecos and four large goldfish, so it is a little overloaded but I have two filters and do 25 percent water change once a week minimum so I've had no problems with the water. Ever. Yesterday I tested the waters and everything within normal range with no nitrites. At 11 o'clock this morning all for my goldfish were belly up. 2 dead, 2 hanging on. Plecos fine but stressed. 

I had no clue what it was so I immediately freshwater added salt and stress coat and grab the four goldfish and put them in the water. Then tested. No ammonia but nitrites were high. Dark purple. 

The only thing that was different than normal was the small top filter hadn't got turned on. But the large canister filter that should be enough to maintain the 60 gallon was working.

The top filter it isn't enough to maintain a 60 gallon and it's just there to help keep my messy fish cleaner. 

Even if the filters had been turned off would nitrite spike in 18 hours? I did give the plecos some zucchini and I'm wondering if there wasn't something on the skin that caused it. I am testing this theory with some of the squash that hadn't got put in the tank.

I did a large water change added prime and salt and I'm hoping the remaining fish stay ok. The nitrite levels were not down to 0 but much lower. The two goldfish are still upside down but I think the stress of everything has caused swim bladder disorder which is fairly common with them. I'm hoping they right themselves fairly quickly.

Now I want to know why. Any guesses?

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## aurielssong (May 26, 2014)

That's scary! I hope you get it fixed!


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## dandries (Apr 6, 2013)

I still don't have a real answer as to what happened but a lot of theories. It's possible that one fish died released ammonia which caused the spike and affected the others is my best guess. I had to only do a 50% water change the first day to get the water parameters back to normal and they remain normal everyday since for the past week. 

That is the only theory that makes any sense and I don't think I will ever know for sure.

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