No nitrates

[Recycledmike]

I have a new tank with 8 zebra danios in it. They have been doing great! Not knowing what I was doing, I added 6 corys and some cardinal tetras. I test my water all the time and nothing ever registers. No ammonia, nitrites or nitrates. 

I have all 8 danios which are fine but I've lost all but one of my corys and all my cardinals. What is going on? If LL these fish are eating and pooping shouldn't I see something when I test the water? 

 

[colo3000]

What are you using to test your water, and are you sure you're following the instructions properly for testing? Also, did you properly cycle the tank prior to introducing fish?

[813aquatics]

How “new” is your tank? Depending on how new it is you may have not had enough time to build up a colony of beneficial nitrifying bacteria in your filter/substrate/surfaces. These are critical to converting *very* toxic ammonia into still toxic nitrite which is then converted to relatively harmless nitrate through additional bacteria colonies.

Depending on your bioload, your initial fish may not have shown obvious signs of distress - and some species are especially hardy to subpar water conditions, danios being pretty tolerant. I could absolutely see a scenario where you add sensitive fish like cardinals and corys and the sudden increased bioload spikes ammonia without sufficient bacteria to break it down. 

It can takes weeks/months to naturally build a suitable bacteria colony and the growth comes in phases typically. Through continuous water testing you should see this process play out. 

As for what you can do this moment….if it is water parameters causing the problem….do daily water changes between 50-90% (treat to remove chlorine/chloramine and try and match tank temperature if you can). I’d also test your water straight from the tap so you know your baseline parameters. You could also try adding something like seachem prime every few days to temporarily convert ammonia/nitrite into less harmful forms (this is a bandaid not a longterm fix mind you). 

If you really want to do things right I would highly recommend contacting a local fish shop and/or facebook local groups and ask anyone for some cycled tank media or a seasoned sponge filter. This will give you an established bacteria colony and solve a lot of your issues. Keep an eye on your fish for labored breathing, red gills, ammonia burns, and test daily if you can. Another tip would be to not clean your filter for awhile and when you do clean it, don’t scrub surfaces just soak your media in tank water until it looks clean-ish. Despite appearances, maintaining a “slimey” filter interior is actually a good thing most of the time. 

If your water turns out to be “okay” I would look next at potential disease that those new fish may have come in with. 

What testing kit/strips are you using? API Master freshwater kit is solid and you can do daily spot checks with Aquarium Coop’s test strips

Edited January 28, 2022 by 813aquatics

[Recycledmike]

I think you may be correct and my tank never actually cycled. I did test both my tap(I'm on a well) and my tank water last night and they are virtually the same. Being new to the hobby, I might(okay... I did) rush everything. 

I understand that Danios are hearty fish, that's why I got them, but shouldn't ammonia be showing up on both API and strips? It's not. 

I over feed sometimes and there are missing fish(I'm assuming they're dead). That alone should create ammonia. 

I was going to skip the water change this weekend and then test my water again late next week in hopes that will supply some answers.