I see many people concerned about their pet fish’s disease so I wanted to write an article about my thoughts. 

There are my personal opinions so please take that into consideration. 

I have been living in America for a couple years now and have just started fish keeping again. 

Before, when I lived in South Korea, I had been fishkeeping for about 7 years.

One of the things I learned while browsing through fishkeeping forums in the U.S.  was how to correctly perform a water test. 

There are a lot of different water test kits but the most commonly used is the AP* company’s. However, I recommend trying different types of test kits. 

In the forums, most tanks with a problem have the following conditions: Ammonia 0ppm

Nitrite 10ppm

Nitrate 30ppm 

PH 7.2

Some people, including me, tend to not care about the measurements and they consider it a waste of money. 

However, after starting fishkeeping in America, I started to use these products because every forum I went to ask for and  talk about these measurements. 

After using it for a couple months, I realized that it is the easiest and safest way to manage tank conditions. 

Water cycle

Ammonia (decomposing food waste, fish excrements) >> Nitrite >> Nitrate This is the order the cycle occurs.

Because nitrate does not decompose into anything, it builds up, which is why water change is crucial. There are other reasons but this is the main one.  

Therefore, it is necessary to know the exact measurements to know if it is really necessary to perform a 50% water change. 

If water conditions are ammonia 0, nitrite 0, nitrate 10,  a water change is not needed. This is an optimal condition for discus. 

Ofcourse, it would be best if the nitrate was 0 as well, however, because tap water contains nitrates, it would be near impossible to achieve this.

The following is a situation I found myself in.

I connected a Fluval external filter called G3 to my tank. The conductivity is shown on the monitor. 

The conductivity measures how much “stuff” is in the water. 

So the more contaminated the water is, the higher the conductivity value would be. 

Looking at the image above, you can see the value increase abnormally starting one to two days ago.

This is very unusual because I have my tank set up on an automatic water change system. 

I was shocked so I tested the tank water with the water test kit. 

This was the measurements. (I measured my other tanks as well)

Nitrate 30 ppm. All other parameters were normal.

So I performed a water change. I tested the water the next morning and the conditions got worse. 

Nitrate became 40 ppm. This is the maximum amount Discus can handle.

So I tested the tap water. There was 50ppm of nitrate in the tap water!

So I stopped performing water change and contacted the apartment management. I told them the tap water is contaminated and the conditions are very harmful for the health. 

They told me they would look into it and let me know. They never contacted me again but fortunately, the water conditions improved. 

In the U.S., the legal amount of nitrate in the tap water is 10ppm and even the annual water report shows 10ppm. However, the water can become contaminated as it comes from the city’s drain and/or apartment/housing drain. 

I believe it is the same in all countries. 

There will come a time when you are diligent about performing water change yet the fish’s condition deteriorates.

Of course it can be due to the tank not being cycled or other problems that may arise, but I am saying that it is possible the problem is the tap water. 

That was my problem. The tap water slowly dripped into the tank and the nitrate in the tap water contaminated the tank. 

Not knowing this, I performed a water change and the water got even more contaminated.

If I was living in Korea, I would have observed the fish scratching, or not eating and then realized there was a problem.

Then, I would have performed a water change and further contaminated my water, thus deteriorating my fish’s health then treating that with medication. With good luck, I might have been able to fix the immediate fish’s health but it would have deteriorated again due to the water conditions and I would have been battling with recurring diseases.

The water test kit can help you correctly diagnose the problem and treat accordingly.

For a long time, I used to rely on my intuition when performing water change but now I believe that water testing kit is a necessary item in fish keeping. 

It allows you to water change efficiently, diagnose the problem correctly and respond in the correct manner.  

Shown below are all the current water parameters from the G3 external filter. 

As you can see, the conductivity dropped significantly. Nitrate is below 20ppm. 

For reference, the normal recommended water conditions are:

Ammonia 0

Nitrite 0

Nitrate 5 ~ 40 

When ammonia and nitrate are above 10, it probably means that it is a newly setup tank or there is a lack of filtration causing the water parameters to be off balance.  

Having high nitrate values could mean there is a lot of nitrate in the tap water or that is has been a long time since a water change was done.

Happy fish keeping!

In conclusion, I am enclosing a video of my happy discus.