white cloud mountain minnows

How to test your fish water and resolving nitrite poisoning

After hours of researching I’m hoping what I have learnt may help people who are having the same issues and questions that I had.

Iv had 7 White Cloud Mountain minnows for roughly a year now and they’ve been fine, however after moving them to a new tank with more fish, a few have started to die.

They previously lived in a glass fish bowl (not very big) with a cheap sponge filter that was barely on, and they were fine.

Now after buying a larger, more conventional and practical tank with a built in light, heater and proper submersible filter, two have died.. and I will tell you why.

The filter sponge needs to hold good bacteria to eliminate the harmful chemicals  (Ammonia/nitrite) that is produced by fish waste and uneaten fish food (this is why you only clean your filter sponges in tank water and not chlorinated tap water). To gain the good bacteria in the filter, the tank needs to be cycled. As my new tank was brand new, with a brand new filter the fish were swimming around in there own pollutants, and the filter hadn’t had the time to build up good bacteria needed to remove it.

Im no expert so correct me if my information isn’t spot on. For the last week however, iv been reading article upon article about fish care, and why my fish were dying, so I’m pretty much a marine biologist by now. I knew the problem was because of the water but I needed to know exactly what it was and how to solve it.

I had to get rid of that ‘oh they’ll be alright’ attitude people normally have with fish. Thing is if you’ve never had many fish or never been able to keep fish, you won’t the complexities involved, just like I didn’t.

To get down to the problem and sort this stuff out I bought the API Freshwater Master Test Kit, after so many people on the internet recommending it and all the good reviews. The kit tests your PH levels, ammonia levels, nitrite and nitrate levels by adding the provided solutions to your water samples in little test tubes included in the kit. You have to then compare the colour of the water to a colour chart.

API Master Test Kit Results, high Nitrite could lead to nitrite poisoning

The Nitrite is a dark purple/pink indicating its 5ppm, very high

It’s really easy and I would advise anyone to purchase the kit, as everyone with fish should have some sort of method for testing their water. My test results:

ChemicalScaleReadingStatus
PH6 – 7.67.2Fine
Ammonia (ppm)0 – 80Perfect
Nitrite (ppm)0 – 55High, poisonous
Nitrate (ppm)0 – 16010Perfect

All was fine except for the nitrite levels were really high on the chart, so by this I now know that it is nitrite poisoning!

After research and speaking to someone who knows their stuff down at Pets at Home I purchased some nitrite and PH solution for a couple of quid. I’m going to apply the solution and do 25% water changes every day, testing the water again until it passes.

Will update when the tank has fully cycled and is in a stable condition.

Updated post: five days later