Gina423

I have a 30 gallon tank, which was FULLY cycled and I bought 4 zebra danios. For two weeks my water was perfect (which was expected of a cycled tank), and so were my fish. But then about a week ago, one fish died. I quickly tested my water which should a slight rise in nitrites (less than .25 PPM) and my ammonia was .5 ppm.

I syphoned the gravel and changed 25% of my water and everything was great. Now today (exactly one week later) my poor danio is struggling to swim. Worrying about the water, I tested my water my nitrites were still less than .25ppm but my ammonia was up to 1.00 ppm!!!!!!

We syphoned the gravel and changed 25% of the water, and thankfully the fish started acting MUCH better, he IS swimming up at the tank more (i assume because that's where most of the clean water is?). I will be testing my water every day to see how it goes?

My questions are:
1. should I be changing 25% of the water every day or every OTHER day?
2. Is it possible that my tank going through another cycle?


Thank you.

bbfeckawitts

Your tank is probably experiencing a mini cycle, which is where somehow some of the beneficial bacteria got taken out or died off. Possible causes are changing the filter media, vacuuming too much gravel, or adding more fish than the bacteria can handle (also if you take fish out for a few days then re-add them). Be care ful not to syphon more than 1/2 of the gravel at a time, even in a cycled tank. You will need to test your water every day and do water changes as needed. You may need to do every day, maybe every other day depending on readings. Don't let your ammonia get over 0.50ppm and nitrites no more than 1.0 ppm.
Brianna

Gina423

So, its safe to do partial water changes every day?

Luniyn

Sure it is safe to do small water changes (like 20%-25%) every day to help keep your levels under control while you get through this mini cycle. Well safe for your fish, your back, arms, etc. while carrying the bucket on the other hand... no so much .

Gina423

Well, that's good. It's just amazing how my poor little fishy could hardly swim and was clearly about to die, I change 25% percent of the water and SNAP just like that he's fine. However, now I have two other questions (I know I'm a pain :


1. Since the water change my fish have been swimming all over the place and appear great, but they are favoring the top-why is that?

2. Should I increase my temperature? And if yes, how does this help move the cycle along?

Thank you!

Luniyn

They are swimming around at the top because Danios are top level swimmers . Each type of fish has a level it likes to stay at, so when mixing various fish it's nice to get some that hang out in one level while another is at a different level so all parts of the tank have activity. And if they are active and swimming like that then you are doing things right... keep up the good work!

As for your temp... no don't increase it. A good level for Danios is upper 70's so if you are around there you are good. Also one side effect of increasing temp (at least while you are cycling) is that you will have a higher level of toxic ammonia in the tank. It's not as big of an increase as your pH being higher, but it's still an increase.

Gina423

O ok, thank you so much

Fishface

my own personal experience with danios is that they swim at all levels of the tank. if you noticed that it was strange for them to be swimming just near the top, then something is off. make sure your water is oxygenated. Mine would swim near the top in the evening when I tried taking my airstone out for the day to see if the plants and current from the filter would provide enough oxygen. When I put the airstone in, theyd start searching for food at all levels of the tank once again.

sgould

My danios are also all over the tank. I have not seen them favor the top unless it is feeding time. If their activity level seems normal, that is a good sign. Watch for red gills, or "gasping" near the surface. Red gills would indicate ammonia problems. Gasping could also be a sign of ammonia trouble, or just generally low oxygen levels in the water.

Luniyn

Certainly if their behavior seems abnormal, then there definitely could be something off. However, you had mentioned that they were going all over the tank but favored the top, which is generally what I've observed in one of the tanks a co-worker owns. He has a very densely planted tank, but it stops about 6" shy of the top of the waterline. His school of about 10 or so Danios will play in the plants, but love to zoom around in the open space at the top (they are the most hyper fish I have ever watched... lol). But as mentioned above, make sure you have good aeration in your tank and watch for problem signs like gasping.