NitrITE spike in cycled tank

[laurelhed]

Help! My 20 gallon tank has been fully cycled for about 2 weeks. A week ago I added 6 Pink Zebra Danios, 2 Red Cherry Shrimp, and a Rubber-Lip Plecostomous. After 3 days I tested levels and ammonia was registering a teeny bit, as was nitrite (not even enough color to actually be on the chart, in both cases), nitrAte at 10ppm. Today my ammonia is 0, nitrAte is 10ppm, nitrIte is 2.0ppm!!! What the heck is going on?!? I did a partial water change and gravel vac when I last tested 4 days ago, I am NOT overfeeding, the pleco does not seem to be eating anything so a couple of pleco wafers have disintegrated in the bottom, but the shrimp have been at them and I will vacuum them today. Any answers out there? Oh yeah, temp is 74, pH is 8.2, I'm using seachem prime in the water.

 

[Iodizedfate]

Did you feed the tank ammo. between when you finished cycling and when you added fish?

Right now my gut reaction is that the algae wafers and sudden influx of fish put the tank in a mini-cycle.

I would vacuum up the wafers and do water changes until your 'trites are below .25 (about 3 50% water changes should do) and just keep a close eye on it.

Pleco's are nocturnal, so he could be eating at night while you're sleeping. Also, they like hiding spots during the day so if you don't have anywhere for him to hide I would consider getting him a shady place to feel safe.

When I would feed my snails algae wafers I would break them in half because I knew that they wouldn't eat a whole one in a night. That helped keep the food rot down and still let me feed the snails.

Do you have driftwood? Pleco's usually need driftwood, it aids them in digestion.

 

[laurelhed]

Thank you very much for your help! I hadn't considered a mini cycle, but I had added ammonia the night before adding fish. As for the pleco & wafers & stuff, I'm doing all of the above! Driftwood, 1/2 wafers, rock cave, still can't see where she's eating and she's not pooping! Anyway, just did a 50% wc and didn't change nitrIte levels at all! NitrAte is down to 5ppm. I will do another wc in the morning, and a third as you suggested. I planned to add 1 or 2 more shrimp and a couple of platys. Do you think that would help or make things worse? Thanks again!

 

[laurelhed]

Oh, I also have 2 anubias, a java fern, an amazon sword, and some java moss.
Thanks!

 

[librarygirl]

So you cycled with ammonia? How long? Did the nitrites rise and fall? How high did you dose ammonia (1,2,4, etc)? My first guess without more info is that you added fish before the cycle completed.

What test kit are you using? A 50% water change should have reduced nitrite by half. Have you tested your tap water for nitrite?

WIth nitrite over .25, I'd suggest doing a few back-to-back 50-70% water changes to get those levels down ASAP.

I would NOT add any more fish right now until these levels are under control. You want ammonia and nitrite to stay at 0 on their own for at least 2 weeks before adding anything else.

Also with the pleco, platys and danios you'd be fully stocked. The Rubberlip may even get too large for your tank, they can grow up to 5 inches so you'll probably need to upgrade as it gets larger (assuming it's small now?) or return it and get a smaller variety of pleco like a Bristelenose.

 

[laurelhed]

Thanks! I did a fishless cycle with ammonia at 4ppm and levels were perfect for 4 days before adding fish. However, the tank had already been going for 4 months with goldfish and a common pleco who were re-homed. I blew it by getting it cycled, then not adding ammonia to keep it cycled, and had to more or less start over!

I am using the API master test kit, and am doing another 50% water change today, and one tonight.

I wanted to stock about 60% of the fish at first, all of them being really small right now. I think the platys will be bigger right off the bat. So yeah, the platys are the last to go in and we are done! Except maybe another shrimp 'cause they're so rad.

 

[librarygirl]

Hm, odd to get a spike if you fully completed the fishless cycle. Did you test your tap water for nitrite?

The bacteria should adjust in a few days or so, just keep up on the water changes until things level back out.

 

[laurelhed]

Thanks for the help!

 

[laurelhed]

Just to follow up, looks like it was a mini cycle. After a couple water changes ammonia was 0, nitrITE was 0 (!), but nitrATEs were 80ppm. So, I just did another water change and will keep testing daily. Thanks again for the advice! Also, do you think adding the platys and a few more shrimp could cause another mini cycle? Only 2 platys and maybe 3 more shrimp.

 

[ejaramillo01]

Just to follow up, looks like it was a mini cycle. After a couple water changes ammonia was 0, nitrITE was 0 (!), but nitrATEs were 80ppm. So, I just did another water change and will keep testing daily. Thanks again for the advice! Also, do you think adding the platys and a few more shrimp could cause another mini cycle? Only 2 platys and maybe 3 more shrimp.

Adding 2 or 3 fish should not start a mini cycle again.