Aquarium Cycling. What's going on?

[OfficialThomas]

Hi everyone,

I have a 20 gallon long that I have had for a little more than a month. I added API quick start and moved over some decor when I set it up and let it run for a couple of days. Then I got 6 corydoras and I let it run for a few more days. I tested water daily and got mostly ( I think one day I might have got 0.25 ammonia so I did a water change) 0 ammonia, 0 nitrite, 0 nitrate, and 7 ph. I moved my betta fish over from an existing tank. Everything was fine until the corydoras starting dying one by one (I eventually moved them to a small hospital tank when there was 3). No water parameters were off and they seemed perfectly healthy except they were swimming to the surface for air (but there was 0 ammonia, 0 nitrite, 0 nitrate). I did a water change anyway. Eventually all the corydoras passed away but the betta fish was and is perfectly healthy and active. I tested my water today and I am still seeing the same parameters! I thought I should be seeing the nitrite and nitrate go up especially since I have fish in it! What's going on?!

 

* I know I messed up the cycling process but I am looking for a way to fix this issue and get the tank fully cycled before anymore fish are added.

Thank you so much,

Thomas

[xXInkedPhoenixX]

Hi Thomas H, 

Simply put, your tank wasn't cycled. Bottled bacteria and things like Quickstart help but doesn't guarantee that your tank is cycled in "X" amount of time. I highly, highly recommend this video from Cory if you are new to the process, to me it perfectly illustrates what happens in a cycle: 

 

Essentially now what you are doing is a "fish in cycle" because you don't have a cycled tank. So you NEEEED to be diligent about checking parameters for the betta often. You will see ammonia come back (change some water, dose with something like Prime to help detoxify), then eventually you will see maybe no ammonia but nitrite (still need to change water, use Prime), finally you will see 0/0 ammonia and nitrite and ideally at first 5 or 10 nitrates. 

The corys could have crashed or disrupted what cycle you did have. They could have gotten sick or were sick and it just goes downhill from there. You have 1 betta in a 20 gallon. It will help speed up the cycle a little but now you have to protect that life by monitoring the cycle as it can be dangerous for them- BUT DON'T LOSE HOPE it can be done- I have done it and lost no fish. 

ONCE your tank is properly cycled then I would highly highly recommend then getting a small tank or container to start a Quarantine tank. There you can add CYCLED material from your now cycled 20 gallon which will instantly help your Quarantine. If it's small depending on the amount of fish you may still need to change water often, like if you get 6 more cory but you have a 5 gallon QT container. Just because it may be cycled doesn't mean you want to overstock without monitoring, 🙂 

I would also give you this tip: add your bottom feeders LAST as they are better benefitted by a cycled tank that has been running a while.

Edited January 31, 2022 by xXInkedPhoenixX

[BettaHomesAndGardens]

On 1/31/2022 at 5:23 PM, xXInkedPhoenixX said:

Hi Thomas H, 

Simply put, your tank wasn't cycled. Bottled bacteria and things like Quickstart help but doesn't guarantee that your tank is cycled in "X" amount of time. I highly, highly recommend this video from Cory if you are new to the process, to me it perfectly illustrates what happens in a cycle: 

 

Essentially now what you are doing is a "fish in cycle" because you don't have a cycled tank. So you NEEEED to be diligent about checking parameters for the betta often. You will see ammonia come back (change some water, dose with something like Prime to help detoxify), then eventually you will see maybe no ammonia but nitrite (still need to change water, use Prime), finally you will see 0/0 ammonia and nitrite and ideally at first 5 or 10 nitrates. 

The corys could have crashed or disrupted what cycle you did have. They could have gotten sick or were sick and it just goes downhill from there. You have 1 betta in a 20 gallon. It will help speed up the cycle a little but now you have to protect that life by monitoring the cycle as it can be dangerous for them- BUT DON'T LOSE HOPE it can be done- I have done it and lost no fish. 

ONCE your tank is properly cycled then I would highly highly recommend then getting a small tank or container to start a Quarantine tank. There you can add CYCLED material from your now cycled 20 gallon which will instantly help your Quarantine. If it's small depending on the amount of fish you may still need to change water often, like if you get 6 more cory but you have a 5 gallon QT container. Just because it may be cycled doesn't mean you want to overstock without monitoring, 🙂 

I would also give you this tip: add your bottom feeders LAST as they are better benefitted by a cycled tank that has been running a while.

I agree with everything said here. The one thing I wanted to add is that if the corys were swimming to the surface for air there could be an oxygen deficiency in the tank as well. Surface agitation from a hang on back filter, a sponge filter or air stone can help. If its a planted tank then overnight and especially in the morning the o2 level can plummet as plants begin absorbing oxygen and releasing Co2. Adding a small air stone or sponge filter on top of ensuring your tank is properly cycled should set you up for success.

[xXInkedPhoenixX]

Totally agreed with @BettaHomesAndGardens AND it can also come from something like ammonia and nitrite poisoning though that may or may not have been the case here. Basically an uncycled tank doesn't have the ability to support life yet. Additional aeration can definitely help during this time- and even in the future depending on your boxed ecosystem. 🙂 

[OfficialThomas]

Wow thanks everyone!

[jwcarlson]

Make yourself a system that makes a water change easy.  I added a bunch to a new tank and jacked up the cycle.  Been doing twice daily 40% water changes checking with strips in the evenings.  Today nitrites were finally low (not zero, but nearly so).  So skipped tonight and will do it in the AM. 

I just age a bucket of water next to the tank with spare heater so it's warm.  My tap water pH swings 1.0+ higher, so aged is the way to go for me.  And an empty bucket is staged there with siphon.  Takes a couple minutes while I'm checking for bacterial infection I'm fighting as well.  If I had to gather stuff and fill buckets it would take twice as long.  But this is pretty darn efficient.

You can WC your way though it.  And with your currently light stocking maybe it's less frequently required.