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Best Water Parameters for Discus Fish

If you are looking into getting started with Discus fish, you know that water parameters are important. The Discus you will be buying is far removed from its home in the Amazon and recreating the exact water conditions found in the wild is not necessary. With a little bit of planning and the right equipment, you can set up your Discus fish to comfy and thriving in clean soft water.

pH Parameters

Let's talk a little about pH, which in simple terms, is how acidic or alkaline the water source is. Measured very easily with a pH meter, first test your water straight out of the tap. A pH meter will let you know if you will need to use special equipment or process the water.

Discus thrive water with a pH between 5 and 7, your best bet is to split the difference with a pH of 6. Lower pH values are tied to [discus breeding](https://tropicalfish.io/article/discus-fish-breedi... but if you are just getting started, you won't need to worry about that for now.

Reading above a pH of 7.5 will begin to stress your Discus fish and can lead to health issues or even death. Be very careful about using chemicals to regulate your pH levels as they may cause large swings in pH values. Try treating your water with peat, use a container or trash can to pre-treat the water you will use for your water change. Then you can aerate and test the pH levels before making your water change.


Discus can do very well in temperatures between 80 and 88 degrees Fahrenheit. Keep in mind the warmer temperatures will cause your Discus metabolism to increase, making them hungrier. If you have a species tank, keeping the tank warmer is great, if you share the tank with other fish, they may not do so well with the higher temperature.

Strongly suggest you use an inline heater that attaches to your canister filter or if you have smaller hang on filter, some come with heaters built in. Discus can get injured or burned by heaters inside the tank. You can even get burned when cleaning the inside of your tank. Don't risk injury to yourself or discus.

Water Hardness

The minerals in your water such as calcium, iron, etc. and is measured in ppm or parts per million. You can easily measure your water hardiness out of your tap by using a water hardiness meter or TDS meter. The TDS or total dissolved solids will vary from region to region, so it is important you know what the TDS value is straight out of your tap. This will let you know if you will require a water pre-filter like an R.O. or Reverse Osmosis unit.

TDS for discus should be ideally between 200 to 300 ppm. Anything lower is reserved for breeding and anything higher may risk the overall health and growth of your discus fish.

Water Changes

Keep your water clean, but how much water do you need to change and how often? For the average hobbyist keeping debris off the bottom of the tank and weekly water changes of about 25% should be just fine. For the more advanced hobbyist and breeders, they are focusing on maximizing discus fish growth and preparing for breeding, naturally, their water changing routines are going to differ. That is where you read about daily or twice daily 100% water changes. If you are not an advanced hobbyist or breeder, your discus will do just fine with weekly water changes as long as you keep your tank clean overall and have a powerful canister filter to polish your tank water.

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