What is the appropriate water temperature for discus fish? The ideal water temperature for discus is between 82 and 86 degrees Fahrenheit. The water we keep our discus in is 84 degrees Fahrenheit. When replacing the water, make sure the new water is at least one degree warmer than what is already in the tank.

How often and how much should I change the water? We recommend changing their water at least twice a week.  Gravel vacuum the substrate, wipe out the aquarium tank and replace at least half of their water. Should you have over the recommended number of discus fish in the same tank, then you should change the water more often.

How many discus can I keep in my aquarium? The general rule is roughly 10 gallons of water per one adult discus. A 215-gallon tank can accommodate 22 discus, while a 55-gallon tank can hold five or six. Unless you plan on changing the water with greater frequency, then I wouldn’t go over the standard limit as it could be difficult, depending on the size of your fish tank.

How many would you recommend purchasing for one aquarium tank? Discus are school fish and thrive in large groups. If you are new to the discus, start with three to five that are 5 inches or larger. If you want to add more over a period of time, then do so in groups. Also, many hobbyists prefer to one of each variety; however, it’s better if you have two of each. They can hang out together, which will make for a less stressful environment.

I have read that discus prefer low pH levels. What is the recommended pH level? Discus are very adaptable to arrange of pH levels from below six to over eight. While a lower pH (6.0 – 6.5) is recommended for breeding, this isn’t necessary. They will be fine in regular pH tap water. The key is to maintain a consistent pH level.

What is water aging? Sometimes tap water has a different pH level than water that has been sitting in a tank. For example, our fresh tap water is 6.8, but after a few hours, it changes to 7.6 or higher due to the degassing of dissolved CO2. Therefore, aging water is recommended to achieve a stable pH should be used when changing the tank’s water. This also eliminates microbubbles. Remember, pH fluctuations should always be prevented.

What about R/O (reverse osmosis) for water? Unless you plan on breeding, R/O water is not necessary. Discus are fine in tap water. The only exception is rock-hard well water (hardness values in the high teens or 20s, tds 450 or more). You might want to mix RO water with tap water to reduce hardness levels to nine or ten (tds 250 or less).

Are bare-bottom tanks necessary? Bare bottom tanks are fine. If you have one, I recommend painting the outside bottom to eliminate reflection. Discus do not like it when fish approach them from below, and bottom reflections make them stressful. There is no reason to have a bare bottom other than to make cleaning easier. If you choose to have a substrate, light-colored rounded gravel or heavy flint sand is recommended.  It looks better and the discus like it.

Can I add decorations to my tank? Of course! Discus like to interact with their environment and have places to hide. Driftwood is fine if it does not have sharp edges or branches. The best is smooth manzanita driftwood. A planted tank is also fine, and although this requires extra maintenance, it does look beautiful. If you prefer a low-maintenance tank, then you should try using artificial plants.

What would be a good background color for my tank? Many of our customers use aquarium tanks with dark backgrounds. Discus will try to mimic the background. For example, a blue strain (Cobalt, Diamond, Snakeskin, etc.) will turn into a more intense blue against darker backgrounds. This is natural and very attractive. Pigeon Blood discus (Checkerboards, Melons, etc.) might “pepper” against darker backgrounds. They cannot darken entirely, so tiny pepper-colored spots will appear. This doesn’t always happen, but it is a possibility. We recommend a light-blue or similar light-colored background. If you cannot change to something lighter, then lighter-colored substrates and decorations are fine.

Should I quarantine my fish before adding them to the tank? Yes. This link will provide you with some excellent information: Guide written by Paul Villenueve on the Simply Discus Forum. Paul has been an aquarist for over 50 years, and I have tremendous respect for his knowledge and guidance. In this guide, he discusses why discus fish should be quarantined. Please refer to the guide for quarantine procedures and other tips on successful discus keeping.

Here is a quote from Paul: “You need to do this as the new fish may be harboring pathogens they are immune to, but the existing fish are not. Also, the stress of the move may cause problems for the new fish, and you don’t want to transfer this to the existing tank. Finally, if the existing discus harbor pathogens they are resistant to, but the new fish are not, then one risks the potential loss of some new fish. Therefore, all new fish, whether purchased from the same source or not, should be quarantined.”