Most of my favorite freshwater aquarium fish come from the Amazon river basin.
This is no surprise given that the region is known for producing some incredible fish that have become immensely popular in home aquariums. Among these is the Discus, a medium sized fish renowned for its distinct circular shape and colorful nature.
In the wild, Discus are found primarily in the main body of the Amazon river. This wild habitat means that Discus have gotten used to constantly being surrounded with fresh, clean water.
As a result, Discus are considered notoriously difficult to care for, requiring large, frequent water changes.
This goal of this expert guide is to help you to build your dream Discus aquarium.
This map below shows the region where Discus come from.
The best aquarium is the one that replicates the fish’s natural habitat. As a result, the first step to building a dream Discus aquarium is to understand the Discus’ natural habitat. The first thing to note is that Discus like stability. Temperature fluctuations, water parameters, and pH fluctuations all have a big impact on the health of Discus. As a result, whatever you choose to do, build a stable aquarium.
There are, however, also some specific parameters Discus prefer.
- Temperature: Discus prefer a temperature of 84 Fahrenheit. They hail from a particularly warm region of the Amazon, and as a result they like warmer temperatures than many other tropical fish.
- pH: 6.5. Discus prefer a lower pH, just a bit under the pH of neutral water. A majority of the fish from the Amazon basin like a pH in the mid-6s. I always recommend you lower the pH of your aquarium naturally, without using buffers and chemicals.
- Water Hardness: single digit dH (2.0-8.0)
- Water Quality: High (Ammonia = 0 ppm, Nitrite = 0 ppm, Nitrate <10 ppm)
- Schooling Fish: Yes
These fundamentals of the Discus habitat mean that they’re some basic minimums to keep in mind when building your aquarium. Here are some Discus “rules of thumb”.
Rule of Thumb #1: Have more than one high-end heater along with a quality thermometer so that you can keep an eye on the temperature.
Rule of Thumb #2: Make sure you have enough space for at least 6-8 Discus in your aquarium. I recommend a 55 gallon aquarium as a minimum.
Rule of Thumb #3: Be willing to do regular large water changes. Make sure you have the correct equipment and time to do a quick 50% water change.
Setting Up Your Discus Aquarium
Now let’s get into the specifics of setting up your Discus aquarium.
To build a Discus aquarium, we need to start with the tank size. Discus are schooling fish that reach a minimum size of 5+” in adulthood. That means that your new Discus aquarium will likely have 6-8 fish each that can grow to an adulthood average of 6”. To hold these fish, I recommend a minimum of a 55 gallon if not a 75 gallon aquarium. This aquarium should also have enough filtration for at least 150 gallons of water.
Personally, AquaClear filters are my favorite. For a 75 gallon aquarium, I’d recommend getting to AquaClear 70 filters. You can put one on each side of your aquarium. As to what medium to put inside, I recommend something foam based designed to hold bacteria. If you want to go cheap, buy some large porous foam sponges, cut them into squares, rinse them up, and put them in the back of the filter.
The next thing to decide is if you want a bare bottom or planted aquarium. There are advantage and disadvantages to both of these. The biggest is a bare bottom aquarium is easy to clean. However, a planted tank better replicates the natural habitat of the Amazon. If you are looking for a centerpiece, I recommend a planted tank. However, if you want a simple tank to raise Discus, I recommend a bare bottom tank.
Since it’s more complicated, for this guide, we’ll assume you’re building a planted tank. If you choose to build a bare bottom tank, ignore the planted tank aspects of this part. A planted tank needs heating, soil, lighting, plants, and CO2.
Let’s start with heating. Start with purchasing two reliable thermometers. As we said above, Discus aquariums need a temperature of 84 degrees, and you need to be confirm that’s where your aquarium is at. I’d also recommend two heaters, each with roughly 3 watts per gallon of water. I hope you’re starting to see a theme here, redundancy. Redundancy is important to keeping your aquarium’s environment stable.
Next, we have to move on to soil. You also have some options here. The top two for Discus aquariums are either ADA aqua soil, great for growing plants, or sand. Sand doesn’t help with plants, but it’s for making your aquarium looking good. Either way, make sure to clean the soil or sand heavily before you begin to use it in your aquarium. Take a bucket and slowly and thoroughly rinse it.
After this, is the lighting. If you have the budget, you can’t go wrong with LEDs. Kessil freshwater LEDs look great. Alternatively, you can go with T5 fluorescent lights. Pick a fixture that fits your aquarium, I’d recommend roughly 3-5 watts / gallon. This number depends on the type of plants that you want. Low level dwarf grass is higher light, while something like Amazon Swords or Java Fern tend to be low light.
Lastly, we move onto the plants and CO2. Which one you choose depends on the look you’re going for here, there’s far too many options for me to lay them out in this article. However, you can buy plenty of cheap CO2 systems online and quickly hook them up. CO2 is also helpful for lowering the pH of your water to slightly below the neutral pH Discus like.
Plants have another benefit here. Traditionally, most aquarium fish like no ammonia or nitrite and medium amounts of nitrate (<40 ppm). Discus like no ammonia, no nitrite, and minimal nitrate. Plants consume nitrate to grow, and as a result, having a heavily planted Discus aquarium can help your nitrate levels stay low. As they grow, they also give your Discus a great place to hide.
Lastly, one major piece of equipment you need is a RO/DI filter. City water tends to come with numerous chemicals, a high pH, and a lot of dissolved salts. Using an RO/DI filter to generate all the water you add to your aquarium could help your Discus. Get a unit that can handle half of your aquarium’s volume on a daily basis, and a Rubbermaid tub to hold the water as your produce it.
Once you have all the equipment, but it all together, fill up the tank with RO/DI water, CO2, and your soil and plants. Then go look at my “How To Cycle An Aquarium” guide to prepare your aquarium for fish.
After putting together your Discus aquarium, it’s time to pick the Discus for your aquarium. We discussed above that Discus are a schooling fish. That means you will want a minimum of 6-8 Discus. Discus are expensive fish, and to buy these 6-8 fish have at least $500 set aside.
Discus are easiest to purchase in-person when you can check their health. However, buying them from a dealer, as long as you can get plenty of pictures and videos can work to. To start, I recommend picking all of your Discus from the same source. That helps to ensure their compatibility and to make sure that they’re used to their same water environment.
Fundamentally, the Discus should look like healthy, happy fish. They should be active, moving around your aquarium, and be responsive to your hand movements. Ideally, you should be able to see the Discus feeding, Discus can sometimes be hard to feet. Overall, the Discus you pick should look happy and healthy. They should have minimal stress and not be hiding away from you.
The next aspect of the Discus to look at are the eyes. Eyes are one of the first signs of illness in fish, so it’s important to take your time here. Make sure the eyes aren’t cloudy, popped out, bubbled, or anything else out of the ordinary. Also make sure that the eyes don’t look out of proportion with the rest of the Discus. Overall, the Discus’ eyes should look healthy.
Next, look at the purely physical aspects of the Discus. The Discus should appear round in shape, have healthy color, and the fins should look proportional with no cuts, tears, or chunks missing. The skin should have no weird spots or deformations and across the entire fish, including the fins, the color should look healthy and vibrant. Again, Discus are an expensive purchase, trust your gut, if something looks off, move to the next one.
Lastly are the Discus’ air and food systems. On top of avidly eating, the Discus’ waste should look well, like poop. Any stringy or white / clear waste could be indicative of a parasite. Parasites are especially worrying, they could give your fish a slow and painful death and spread to your other fish. As a part of this, the fish should look like it’s taking regular healthy breaths, with no apparent damage to its gills.
Once you’ve picked your Discus, if your aquarium was previously cycled and empty, you can add them together in. If your aquarium has had fish their previously, use a quarantine tank. I’d recommend keeping them in the quarantine tank for a few weeks before adding them. Either way when it’s time to put your Discus in other water, you need to acclimate them.
Before we acclimate Discus, the first step is to understand the point of acclimation. The point of acclimation is to minimize the stress your Discus face. As a result, it’s important to never rush the acclimation process, keep the aquarium lights off, and not feeding them for the first day, to help them get used to their new environment.
To acclimate a fish as expensive and difficult to care for as Discus, I recommend using the Drip Method, an advanced but slow acclimation method. To use this method, you need a 1 gallon clean bucket, another small bucket that’s never been used for anything else, and some airline tubing. These two things can be bought for $10. I recommend also purchasing some airline clamps that can hold the airline to your bucket.
To acclimate Discus, start by closing any window shades, and turning of the lights in your aquarium. After doing this, place the sealed bag with the Discus in your aquarium so that it floats. Leave the bag floating for 15-20 minutes to let the temperature between the back and your aquarium equalize. This might take a little longer, Discus are used to warm temperatures, it wouldn’t hurt to leave it for 10 minutes or so extra.
Now empty the bags with their fish and water into the buckets. Hopefully you have enough water so that your fish are fully covered. If the fish aren’t fully covered, you’ll have to slightly tilt the buckets until there’s enough water. Now run the airline tubing from your aquarium to the bucket so that it begins to transfer water, and then bend or tie the airline tubing some so that you get two drops per second.
You can also buy an inline control valve for the airline tubing to control the flow of water for just a few dollars.
To do volume calculations, a water flows at about 25 drops to the mL. Now let the water flow. Once the water reaches twice the original volume, remove just enough so that the fish are still fully covered or half the water, whichever is less. Continue this process until you’ve removed water a total of 4 times. At that point, 93.75% of the water will be water from your aquarium, 6.25% will be original water.
At this point the fish can be transferred back to the aquarium. Submerge the bucket with the Discus in the aquarium and let them swim out. At that point, your new Discus have now been added to your beautiful aquarium.
Now you have a Discus aquarium setup and some beautiful Discus acclimated in the aquarium. The first thing to know about feeding your Discus is how old they are. Discus less than 12 months of age should be fed 5-10 times a day (closer to 10 if they’re younger). Discus more than 12 months of year should be fed 2-3 times per day, a good rule of thumb is to feed them whenever you eat.
As with all fish, the rule for feeding is don’t feed them anymore than they can eat in 5 minutes. There’s plenty of different things Discus love but there’s some important guidelines to follow. First, Discus tend to be picky about their food, so do not always follow what you feed them online but also look at what you’re Discus is willing to eat. If you’re Discus refuses to eat beef heart, that’s fine.
Another thing to keep in mind is that standard fish food isn’t nutritional enough for Discus. And Discus like a variety of food. On top of that, plenty of people recommend live food such as live bloodworms for their Discus. Live food is great nutritionally for Discus, however, there’s a chance your Discus could get parasites. As a result, I recommend avoiding live food for your Discus.
Past these guidelines, there are a number of common foods that Discus love. I recommend beefheart flakes, frozen bloodworms, discus flakes, and frozen mysis shrimp as some to begin with. However, there are plenty of other quality foods to checkout. It also depends on if you want to deal with frozen food, which is higher in quality, but obviously also needs to be frozen, or if you want to deal with freeze dried food. Live food is even higher in quality than frozen food but is messy to prepare and can transmit parasites.
If you’re lucky enough to have unpicky Discus, I recommend mixing a number of foods together, perhaps all the foods I discussed above, and feeding it to your Discus together. That will help provide them with a varied and consistent diet. Another thing I’d recommend doing is asking your supplier what they feed their Discus when you first purchase the fish. Start with that, and slowly change it up if you want to
Now that you’ve built your dream Discus aquarium it’s time to discuss a maintenance schedule. Discus like clean aquariums and you need to do regular water changes. I recommend doing a 50% water change daily in your aquarium. On top of this, let’s assume you have 3 biological filter sponges in each of your aquaclear aquariums, for 6 sponges total.
I recommend changing one of these 6 sponges every two weeks.
Now onto the water changes, a 50% water change daily. I know it sounds crazy, but stick with me here. For starters, we discussed above that we want to be using RO/DI water in the aquarium. I recommend having a separate rubbermaid storage tub that holds RO/DI water. This separate rubbermaid storage tub should be twice the value of your entire aquarium.
Have a heater in this separate water to keep it at 84 degrees along with some air pumps to provide some circulation. On top of that have a pump in here with a line hooked up to your aquarium. The goal is to keep this separate water with the same parameters as your Discus aquarium. Then everyday, when you want to do a water change (I actually recommend a 25% change in the morning and a 25% change in the evening) it’s simple.
Have a vacuum water changer with the line running to wear you dump water (your grass, a shower, whatever). Then remove water until you reach your target. The larger vacuum water changers can do a few gallons per minute, meaning for a 75 gallon aquarium you could do a 50% change in less than 10 minutes. Then with your pump in the rubbermaid tub, with tubing hooked up to the tank, flip a switch, and the water will be refilled in <10 minutes.
Once you get it down you should be able to do a 50% water change on a 75 gallon aquarium in <15 minutes.
Building your dream Discus aquarium can be a long and hard task. However, it can be incredibly time consuming and easy to make mistakes. Despite that, if you spent the time, I believe that it can be an incredibly rewarding experience.
Let me know if you have any suggestions or opinions in the comments below, I look forward to reading them.