Discus are arguably one of the most beautiful fish in the freshwater aquarium hobby. However, this species creates hesitation for aquarium owners that want to begin keeping them at home. There are countless debates among Discus enthusiasts regarding proper care but each case is unique to the fish and its owner. There are several universal guidelines to follow in setting up a tank intended for Discus. Despite various opinions on RO vs. Tap water, lighting, plant types and food; these guidelines are intended to help you get started with your Discus tank.

Choosing a Proper Aquarium and the Gear

Generally, the minimum size recommended for a Discus tank  is 50 to 60 gallons. You’ll need a larger tank if youre going to have several Discus in one tank.

Water quality is very important to Discus. A filter that turns the tank over at least five times per hour is necessary. However, even more water turnover is suggested for better results.  In this case, eight to ten times per hour is ideal for optimal water quality. An easy way to figure out how many times a filter turns water over per hour is to divide the fitler’s GPH by the size of your tank. If you have a minimum of a 50 gallon tank, some filters that turn water over 8 times or more per hour include:

Discus need to be kept quite warm, so more heater power is necessary. Five watts per gallon of water is a minimum for your heater, and it is a very good idea to add a second heater.  If a heater goes out on your tank, the second heater would keep the temperature stable. You don’t want the water temperatures to plummet!

A secure top for your aquarium is also crucial. Glass is generally a good choice because it allows for more lighting options if you have live plants.

Substrate (gravel) will also vary by personal opinion and by function. Some recommend a bare bottom while others will suggest a thin layer of gravel. Hobbyists who keep live plants will usually want a specialized plant substrate to encourage good root growth.

Getting the Tank Ready for Discus

Once your tank is equipped and ready, it’s important to start the aquarium through its normal biological cycle.  Please note, a new tank should not be cycled with the Discus. It should be cycled with other, more durable fish. You can cycle a tank with almost any freshwater fish, but the fish you choose will depend on your ultimate goal.

    1. Discus-Only Tank – Cycle your tank with Tetras, Rasboras, Danios, livebearers (such as Guppies, Swordtails, Mollies, Moons, or Platies), Gouramis, or the like. All these fish will be re-homed at some point, depending on when you intend to add the Discus.
    2. Discus with some helpers – Cycle your tank with the same fish as a Discus-Only tank, but also include Corydoras and/or Otocinclus Catfish to help with cleaning the bottom of the tank. Corycats, as Corydoras Catfish are sometimes called, prefer to be in groups of at least three, with five to ten Corycats being preferred. Otocats, as Otocinclus Catfish are sometimes called, do not have a preference with how many are kept in the aquarium. The Catfish will end up staying in your tank long-term, but the other fish will be re-homed, depending on when you intend to add the Discus.


  1. Discus with some helpers and “Dither Fish” – Cycle your tank with small Tetras (such as Rummynose, Cardinal, or Neon), Corydoras Catfish and/or Otocinclus Catfish.Since Discus can be shy, small Tetras can act as a type of security blanket. Typically called “Dither Fish” in this situation, the small Tetras are not shy and will come out to eat or swim. The Discus see the “Dither Fish” out in the open and feel safe enough to join.The “Dither Fish” prefer to be in large schools. At a minimum, you should have 12 of the same small Tetras, with schools of 20 or more being preferred. You can have one extremely large school of the same small Tetra, or do multiple smaller schools of different small Tetras, depending on your preference.

    Corycats, as Corydoras Catfish are sometimes called, prefer to be in groups of at least three, with five to ten Corycats being preferred. Otocats, as Otocinclus Catfish are sometimes called, do not have a preference with how many are kept in the aquarium. The Catfish with help with cleaning the bottom of the tank. The small Tetras and Catfish will end up staying in your tank long-term, living with your Discus.

After several weeks, the tank will be cycled. Depending on your ultimate goal, there are a few options for handling the fish you used to cycle your tank.

    1. Discus-Only Tank – The fish used to prepare the tank can be given to friends, donated to local pet stores, donated to local fish clubs, or create a peaceful community tank at your home – if you want more than one aquarium.


    1. Discus with some helpers – Keep the catfish. Re-home the rest of the fish in the same manner as you would for a Discus-Only tank.


  1. Discus with some helpers and “Dither Fish” – You won’t need to find homes for any of your current fish. Just get ready to add Discus!

After re-homing the fish you intend to re-home, your aquarium should then be ready for the introduction of your first Discus. Generally, three to five Discus can be housed with relative comfort in a 50 gallon size tank. Larger tanks will allow more fish, and the general rule of thumb for Discus is one fish per ten gallons.

Your tank temperature for the Discus should be increased to the middle 80s, and they will handle temperatures in the upper 80s and still be relatively comfortable.

Choosing the Right Discus

At PetSolutions, our Discus breeder has been in business for 35 years and is based in Germany with US distribution from a location in the United States. We bring all of the fish here to our freshwater facility, where they are placed in specially prepared tanks for quarantine and observation before they are allowed to ship out. PetSolutions Discus are used to a mixed diet of frozen foodfreeze-dried foods, and Discus-specific pellet food. Our Discus breeder is a winner of many American Cichlid Association awards, including Best Discus in Show. The Discus we ship from our facility are already carefully chosen to be excellent specimens and have been proven to be nearly bullet proof.

If you are choosing Discus on your own, however, there are several things to look for.

  • The fish should be active.
  • As you approach their tank, observe the behavior of the fish. Watch if they react to you by swimming toward you as if to say, “Here comes the person with the food,” or if the fish hides in a corner and cowers in fear.
  • The fish should have clear fins with little to no splits in either the fins or tails; it should also have clear eyes.
  • Request that the seller feed the fish in front of you. Observe both what the seller is feeding as well as how interested the Discus is in the food.
  • If the seller feeds live food, such as live worms, ask if they can feed a frozen or freeze-dried food, instead, and observe if the fish will eat those foods. Your ability to keep the fish healthy at your home or office will depend partly on your ability to keep them well fed. If the fish eats only live foods, you would need to have constant access to live foods, and that is not always possible. Discus will quite readily eat frozen and freeze dried foods, such as beef heart, bloodworms, and commercially prepared frozen Discus foods. Discus-specific pellet foods can also be used, in conjunction with freeze-dried and frozen food.
  • Body shape on a Discus is important; they should have a very round shape.

Maintenance for Your Discus Tank

Regular water changes, either with de-chlorinated tap water or with Deionized or Reverse Osmosis purified water, is generally considered extremely important in a Discus tank. Weekly water changes of ten to fifteen percent of the water in the tank will not only help with the quality of the water and the color of the fish, it will also encourage quicker growth in the fish.

Replacing the media in filters on a regular basis is also important, usually once each month.

Setting up lighting on timers is a good idea for any aquarium, so it will give the fish a regular day and night cycle. If there are live plants in the tank, this also keeps the plants from getting too little or too much light.

All of these things are just a touch on the surface of keeping Discus. Anyone with a couple of years of experience keeping tropical fish can make the plunge into Discus keeping. You will most likely have good success as long as patience is used and proper feeding, equipment and water quality are in place. There are a variety of websites focused on Discus available on the internet, and there have been many books on Discus published. It is recommended to read and research as much as possible before deciding to make the switch to these wonderful fish, but most who make the change never look back.

Editor’s Note: This post was originally published in September 2010 and has been completely revamped and updated for accuracy and comprehensiveness.

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