Why is my nitrate levels high in my freshwater aquarium? I am sure like so many other fish keepers you have used a nitrate test kit and discovered your nitrates are through the roof, for some of us this is not a panic station moment, for others not so much. But what has caused the high nitrates?

High nitrates are generally caused by a lack of aquarium maintenance, but they can also be a sign of overstocking or over-feeding your aquarium fish. Too many fish produce more waste than the bacteria in your aquarium can process which results in the excess fish waste becoming highly toxic and fish may even die of nitrate poisoning if left unresolved.

How do you lower your nitrate in an aquarium? One of the easiest and fastest ways to deal with a high nitrate level is to perform a water change. This is because you are physically removing the nitrates from your water and replacing it with fresh clean nitrate-less water. But this might just be a stop fix, as it hasn't gone to the root of the reason for having high nitrates.

If you are getting high nitrates on a regular basis, you could try feeding less. As mentioned before overstocking or overfeeding can be a cause of high nitrates so reducing your fish population could go a long way to reducing the levels of nitrate in your freshwater tank.

Live plants can also reduce elevated nitrate levels. They utilize nitrate as food to grow (they also look cool) but not all aquariums can have plants in them. Often people overlook filter maintenance, which can result in a gradual increase in nitrates, try cleaning out your filter sponges slightly more often and discarding your filter floss on a more frequent occurrence. Additionally, the use of nitrate removing filter bacteria may be something to consider.

Have a look at or useful water care range here