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Water Temperature

If you maintain a steady temperature in your tank, you can actually help keep your discus healthy. In this article, we'll give you everything you want to know about your water's temperature and how to maintain it at a healthy level.

Blue-Faced Heckel Discus

What Is the Ideal Temperature For Discus?

The ideal water temperature for discus is around 86 degrees Fahrenheit.

What Happens If The Water Gets Too Cold?

Your discus will get sick. To understand why, imagine their native habitat: the waters of Brazil, which are constantly warm. Discus genetics are encoded to thrive in a warm environment. If the water stays cold for several days, even the healthiest of discus will become weak and sick.

What Happens If The Water Gets Too Hot?

It would suffocate your discus. When the tank water gets warmer and goes above 90 degrees for too long, there is less oxygen in the water to go around. What you will see long before your discus suffers permanent damage or death is them gasping for air near the surface of the water.

If you over heat your tank, do not put ice or cold water into your tank. Simply drop a few more air stones to aerate your water, and these will speed up the cooling process as well as provide much needed oxygen in your tank. Of course, don’t forget to lower your heater's temperature.

How Should I Regulate Water Temperature When Adding New Water to My Tank?

When you change your tank's water, you may want to have another heater around to bring the new water up to the appropriate temperature. This is more important for those who live in colder climates, or who are in rooms with a temperature below 70 degrees Fahrenheit.

Immediate swings in water temperature can kill your discus as well as any other fish for that matter. 

Keep the water that you are using for the water exchange at the same temperature as the tank. Try to match the water's temperature to the tank water's temperature before pouring the water in.

Where Should I Place My Tank?

Avoid placing your tank near windows or drafty areas. In some areas, temperatures can drop 20 or more degrees Fahrenheit overnight, requiring your heater to work overtime to keep the water temperature constant. If your heater is not strong enough for this task, it may short out.

Put the tank in a place where the sun will not cook the discus during the day, and a window will not freeze the discus overnight.

Large Red Passion Discus


  • Why is your water's temperature important?
  • Do you have a system of keeping tank water constant?
  • What temperature do you like to keep your discus tank at?
  • How will you make sure your water remains at a safe temperature?