20 Gallon Tank Huge Nitrite Spike

Have a 20 gal tank that has been cycled for a while now. My tank is currently inhabited by a dwarf gourami, bumblebee catfish, 3 Ghost shrimp and an ornate bichir (I'm growing him larger before he goes in the large tank.) The tank was cycled when I put the ornate in. I removed some serape tetra's shortly after I put him in due to issues of them possibly fin nipping, and added the catfish. I'm not sure what has happened but I have stopped receiving Nitrates, and only receiving nitrITES now. Ammonia is at 0.75ppm, pH is at 7, and the nitrites are out the roof. Roughly 10ppm if not more. I have three live plants and some other décor and hiding places for the catfish and bichir. Also some driftwood. The fish are not acting lethargic and are still accepting food, though I've stopped giving them as much food recently due to the nitrite spike.
I went through something similar with my 65gal earlier this year and it is now fully cycled. I've put the filter media from the 65 gallon in this tank to see if I could help speed along the nitrites going down but that hasn't really helped. What's going on?
Should I change my filter media? I've done two 50% water changes with no change in nitrites. I've attempted to dose with PRIME and no affect on the nitrites, it still maxed out the API test and the dip test. I would have never known this was going on if I didn't use a quick dip test kit and was quite confused to see the nitrites through the roof.

I have no idea what has caused this spike. I have a few options as this has been going on for over a week now. I could move my fish over to the larger tank, however, the ornate bichir is about 5" long and is still quite thin. I am afraid he may get eaten by my large fully grown senegal bichir in that tank. I seem to have the roughest time with cycles, as this is the second time I've "lost" the cycle or something like NTS..

 

What kind of filters do you have and how are you cleaning them? Prime will not "remove" nitrites or ammonia it just makes it a safer form. Do you have a pic of the API tube?

 

What kind of filters do you have and how are you cleaning them? Prime will not "remove" nitrites or ammonia it just makes it a safer form. Do you have a pic of the API tube?

Hi Stargirl, You have helped me before and I am happy to see you here. Its an aqueon filter, it holds the large filter pads and the smaller pad at the output. I haven't cleaned them, but I assume you mean cleaning them in aquarium water outside the tank. The reason I dosed with Prime is that it says it helps the BB clear out nitrites, but I guess that's just for emergencies (Which I think this is.) Here is a photo of the test tube.

 

Prime is just dechlor that will help with Ammonia and Nitrites. It has to be under 1ppm though. I would keep changing water until it goes down. Maybe do 75% next time and see if it went down any.

 

Prime is just dechlor that will help with Ammonia and Nitrites. It has to be under 1ppm though. I would keep changing water until it goes down. Maybe do 75% next time and see if it went down any.

Do you believe the fish will be alright with the 75% change? I am already running fresh water to make the process as quick as possible. Edit: I have two 5 gallon buckets filling up ready to be dosed and ensured to have the same pH as the tank is what I mean.

 

Yes... better than those really high Nitrites, they are as bad or worse than ammonia.

I am still curious as to why they all of a sudden jumped like that.

 

Yes... better than those really high Nitrites, they are as bad or worse than ammonia.

I am still curious as to why they all of a sudden jumped like that.

I've allowed the tank to settle for a bit since the change, Readings are around 7.2pH, 0.25 ammonia or less (very hard to tell.) 0.5 nitrite, 5 or less nitrates. Its as if the tank went through a mini cycle and the nitrites just went out of control for some reason. What to do if this happens again? I did not suction the sand as it wasn't quite dirty, only grabbed a few bits of poo.

 

Change water...... the only thing you can do. LOTS of water to get it back down. How much do you change weekly?

 

Change water...... the only thing you can do. LOTS of water to get it back down. How much do you change weekly?

Its typically 20% every 7-10 days