Ideal TDS for a cory catfish? (All You Need To Know.)

Ideal water parameters play a vital role in keeping your fish healthy and ensuring their longer lifespan. Your tank’s TDS level should be ideal as too high or low TDS can affect your cory catfish health. So, let us discuss the ideal TDS for a cory catfish.

400-600ppm is the ideal water TDS for a cory catfish. Too high or low water TDS level will stop their growth, and also their health will be affected. Ensure regular water changes, avoid overfeeding, and run proper tank maintenance to maintain the ideal TDS level.

This article will discuss a cory catfish’s ideal TDS level and water parameters. Also, we will discuss how to reduce the water TDS level. So, let us get into it.

What is the ideal TDS level for a cory catfish?

The ideal TDS level of your cory catfish is between 400-600ppm.

They will thrive between these water TDS levels.

The water TDS level plays a major role in keeping the water chemistry ideal for your cory catfish.

Too high or low TDS levels can make your cory catfish suffer from life-threatening issues.

So, checking the TDS level in a regular manner is essential to ensure your cory catfish’s good health and development.

Also read: Ideal Temperature For Cory Catfish?

Cory catfish ideal water parameters?

Cory catfish are hardy fish and can live in a wide range of water parameters.

Provide them with a water temperature between 70-82 °F.

Keep the water pH level between 7 and 8.

Ensure to maintain the water TDS level between 400-600ppm.

The water hardness should be between 5 and 19 dGH.

Also, consider adding a heater to your cory catfish tank to keep the water temperature stable.

Unstable water temperature will make your cory catfish under stress and become prone to various diseases and parasites.

How does high TDS affect your cory catfish?

The density of TDS in the water controls the flow of water in and out of your fish cells.

Too much high TDS can affect your cory catfish’s growth and development.

Also, a high TDS level will result in algae bloom in your cory catfish tank, making the water conditions poor.

Too much algae in your cory catfish tank will result in a defeciency of oxygen in the tank.

A high TDS level can even result in your cory catfish passing away.

How to measure the TDS level of an aquarium?

You can measure the TDS level of your cory catfish tank by using a digital TDS meter.

You can get the digital meter online or at pet stores.

We recommend using this TDS digital meter as it shows accurate results and is easy to use.

All you have to do is put the TDS meter inside the water to the maximum immersion depth and check the water temperature first.

You will have a switch by which you can set what you want to check.

After checking the water temperature, set it to the TDS and check the TDS level in the same way you have checked the water temperature. 

What are the reasons behind the TDS spike in my cory catfish tank?

A poorly maintained and dirty tank is the only reason behind the TDS spike in your cory catfish tank.

The TDS level of your cory catfish tank will increase with every addition of plant fertilizers, algae relief chemicals, substrates, uneaten foods, and other waste.

Even when you will treat the water with the water conditioner, it will raise the TDS level.

Overfeeding your fish will result in a spike in the TDS level of your aquarium.

Performing a regular water change and running proper tank maintenance will help maintain the TDS level.

How can we decrease the TDS level?

Ensure these things to balance the TDS level:

  1. Perform a regular water change
  2. Avoid overfeeding your cory catfish.
  3. Perform regular maintenance of your tank.

Regular water change

The TDS gets built up over time in an aquarium, and regular water change is essential to maintain it.

Consider regularly performing a weekly water change of at least 35% to reduce the water TDS level.

However, how often to change the water will depend on how fast the water TDS increases in your corydoras tank.

Keep a regular check on the TDS level by using the TDS meter.

Performing a water change will help you keep your cory catfish tank clean from excessive waste and toxins.

All these waste and chemicals increase the TDS level, and eliminating them by performing a water change will help you maintain the water TDS level.

Avoid overfeeding

Cory catfish are bottom dwellers that spend most of their scavenging on the bottom, searching for food.

They will feed on leftovers and other waste from the bottom of the tank.

However, relying on them to entirely keep your substrate clean is not a good decision as they also will not be able to feed on every waste.

Cory catfish will only feed on food leftovers, dead and decaying plants, and small dead fishes.

They will not feed on fish waste and any other types of waste.

So, overfeeding will result in more fish waste in your cory catfish aquarium, resulting in a spike in TDS.

So, avoid overfeeding your cory catfish and other fish in a tank as it can result in a TDS spike, and also, overfeeding will cause constipation and bloating to your fish.

To ensure that you are not overfeeding your cory catfish and other fish, provide them food in a quantity that they can finish eating in one to two minutes.

Perform regular maintenance

Doing a regular water change will help you keep the water clean.

However, you cannot keep the aquarium super clean just by performing a water change.

Some waste gets stuck in the aquarium wall and substrate, which cannot be clean by performing a water change, and we have to clean it by ourselves.

Also, cleaning the filter on a monthly basis is essential to maintain the TDS level.

The water filter will also get dirty over time by the buildup of waste, so it is important to clean the filter to avoid unwanted waste.

The only way to keep the TDS level at an ideal level is by keeping the tank clean from leftovers, chemicals, and other waste.


The best TDS level for your cory catfish is between 400-600ppm.

Too high or low TDS levels can make them suffer from various issues, and it will affect their growth as well as they can even pass away.

Poor water conditions, overfeeding, and improper tank maintenance result in a spike in TDS levels.

There is already some amount of TDS in tap water. The TDS keeps increasing with leftovers, plant fertilizers, water conditioners, nitrite, nitrate, Fish waste and leftovers, and other solid molecules.

So it is essential to keep the water clean by performing a regular water change, avoiding overfeeding, and running proper maintenance of your tank to keep the TDS at an ideal level.

Reference: ResearchGate, ScienceDirect

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