'Safe' Ammonia and Nitrite levels??

[Jmunroe]

That's your problem then. You can't leave rotten food in there

 

[OwduaNM]

Checked today, Ammonia was 0 but Nitrites were elevated. Did a 50% WC and will check again tomorrow.

 

[paul65]

I was just thinking that was the problem. I left all of the decaying fish food at the bottom of the tank and didn't clean it out before adding the Danios. I cleansed up a good portion of the food with the water change yesterday. I will be more thorough today.

I have also reduced the amount that I am feeding them since I suspect I was feeding too much.

The one good thing to come out of this is that you have danios in there, these are the most hardy fish i know and will happily survive in less than perfect water conditions so you made a great choice there. Follow the advice you have had ( especially the water changes ) and you will be fine. Regarding the feeding you will learn from experience exactly how much to give them, less is more in terms of feeding and if they all get a bit then they will not starve