Discus are known to be very difficult to care for. But, once you have some experience with fish keeping, that shouldn’t deter you! While they may take more time and attention than your average freshwater fish, Discus are one of the most beautiful species in the trade. Their gorgeous colors and fascinating behavior are well worth the extra effort. Keeping a large Discus tank in your home is sure to be the centerpiece of any conversation. This guide will walk you through setting up your first Discus aquarium and the factors you will need to succeed.
Tank: 55-gallon minimum, though 75+ is recommended – you can keep larger numbers of Discus, which will make them happier
Filtration: Low to moderate water flow required; low for juveniles, low to moderate for adults
Heater: Discus are most comfortable in higher tropical ranges
Thermometer: Make sure your heater works properly and maintains a stable temperature
Large Nets: Discus grow up to up to ten inches – make sure you have nets that will accommodate their adult size.
Quarantine tank: If any of your Discus or their tank mates become ill, they must have a separate space for treatment and recovery. They may infect other fish if left in their main aquarium.
Test Kit: The water in which Discus are kept must be pristine – the only way to ensure this is to test frequently
Tank Cleaning Supplies: Designated buckets for clean water and dirty water, water siphon, sponges, de-chlorinator for water changes, glass or acrylic safe scrapers/sponges, towels
Aquariums come in all sizes and shapes, but different fish require different types to be happiest and display their best colors and activity level. Because of their tall, slender bodies, Discus fish prefer to be in a tank that is also tall. They are also medium to large-sized fish, reaching eight to ten inches when fully grown at around two years old. Because of this, and because they prefer to be in large groups, the bigger tank you can offer them, the better. We recommend no smaller than a 55-gallon, though 75+ affords you a higher chance of success.
Like most tropical fish, Discus need to have tropical water temperatures to be happiest. Unlike most tropical fish, Discus like things just a little bit hotter than others. When purchasing Discus that were farm or tank raised, they usually come from waters around 86-88°F, although some species come from water that is 90°F or more. While they can tolerate slightly lower temperatures, such as 82°F, we recommend keeping your tank at a steady 85-86°F. After your Discus have become acclimated to this temperature, you can adjust to slightly higher or lower temperatures if you need to to make your Discus tankmates (if you have them), more comfortable.
Maintaining a stable pH in your Discus aquarium is one of the most important aspects of keeping them safe and healthy. While they can tolerate a pH anywhere between 6.0 and 8.0, it’s important that whatever level you choose, you faithfully stick to it. Changes in this parameter can shock your fish and even kill them. Most tap water has a pH of around 6.5-7.5, which is well within the range for Discus, provided dechlorination additives are used.
However, tap water often contains carbon dioxide, which will raise the pH as it dissipates. All you have to do to get rid of the carbon dioxide is to let it sit. Test your water straight from the tap. Then fill a large container, such as a five-gallon bucket, and test the water again after letting it sit for twenty-four hours. If the difference in the two pH levels is .3 or less, it is safe to use your water straight from the tap, provided it is at a suitable temperature. If the difference is higher than .3, you will have to ‘age’ your water in containers.
If your tap water does not fall within the recommended ratios, use deionized water or reverse osmosis water, or use one of our methods to naturally lower your pH.
Rivers are the natural habitat for Discus. While river water flows at several different strengths, the home for Discus fish are slow to moderate moving rivers that wander through the landscape. This type of water flow should be replicated in the home aquarium. When Discus are full-grown, they can handle waters that are a little faster moving. However, juveniles won’t be happy unless water flow is kept to a minimum. Having a filtration system with adjustable water flow is advised. This way, you can have a lower water flow for when your Discus are young, then a higher flow when they are older to help keep your water clean and aerated.
There are two options for setting up your Discus aquarium: planted or bare. Planted aquariums make for a beautiful display piece in your home, but they require more maintenance. Because Discus tanks already require vigilant upkeep, this increases the already demanding work put into keeping them. With planted tanks, you must keep fewer fish because of the tank space taken up by substrate, plants, rocks, driftwood, and decorations.
If you do decide to go with a planted tank, there are some suggestions you should follow. Discus like to graze along the bottom of their homes, so use a fine to medium-grained sand. This replicates their natural habitat and makes grazing safe and easy. Plants must be compatible with the higher temperatures that Discus like and have broad, flat leaves. They appreciate driftwood and rocks set up vertically, which mimics tree roots, downed limbs, and the relatively obstruction-free bottom of the middle of a river bottom.
Bare tanks, also known as bare-bottom tanks, are far easier to maintain. Just because ‘bare’ is in the name doesn’t mean there can be no decorations at all. It just means that there is no substrate to vacuum, and very little added to the tank that must be cleaned. This is the preferred set up for many Discus owners, and what we recommend for beginners.
You should consider several things when choosing your new Discus, the first of which is where to get them. There are generally three ways to purchase Discus: from a local breeder, online, or a local fish store (LFS). We recommend that you don’t buy from a local fish store. Since they take so much time and so many resources, Discus are not good sources of profit. If they have them in the first place, LFSs generally do not have the capability to care for Discus long term.
Local breeders and online retailers both have their advantages and disadvantages. With local breeders, the advantage is that you can see specimens in person before purchasing. However, there is often a limited number of options when it comes to variety. With online retailers, you have a wide array of choices, but you can’t view the fish and select the individuals you want. With both of these options, word of mouth is critical. They both have to have a good reputation among Discus owners to be in business for any length of time, so make sure you ask around and read reviews. Before purchasing from a local breeder, see the fish in person, ask questions about their upkeep and water parameters, and ask to see them be fed.
When choosing individuals for purchase, look for Discus that are circular, not football-shaped. Their eyes should be clear and well proportioned to their bodies. Eyes that are cloudy, overly large, or protruding are signs of inferior stock. In color, they should be bright and vibrant, their fins should not be clamped to their body, and they should have a steady, not rapid, respiration rate. Any of these things are indicators of sickness and stress. Lastly, Discus are known for their ‘showy’ behavior. Shying away from the front of the tank when you approach or if they seem to be hiding, these can also be signs of stress or illness.
The best way to acclimate your new Discus to the home you have prepared for them is to find out the conditions from which they come. Any online retailer or local breeder should be able to answer questions about how their fish are kept, so don’t be shy! When you get home, place the bag containing your Discus into the tank to equalize the temperature. This will take approximately 20 minutes. Next, check the pH level in the bag water and in your tank. If there is a .3 or less difference, you can now add the fish. Using a net, pour the bag water into a bucket. As each fish enters the net, stop pouring and add the fish to your tank. Continue this until all fish are in the aquarium. If there is a higher than .3 difference, slowly add water from your tank to the bag. This should be done over an hour until there is around a 50/50 ratio of tank and bag water mixture. Then, add fish to the aquarium using the method described above. Never add water from the bag to your tank.
Water changes and tank cleaning are crucial to the health and happiness of your Discus fish. They do not tolerate any significant changes in their water parameters, so you must extremely diligent with maintenance. Because Discus produce a considerable amount of waste and shed mucus layer that quickly fouls water, they need partial water changes frequently. How often you should do water changes depends on several factors: how many fish you have, how much they are fed, whether you keep them in a planted or bare tank, etc. Having a test kit is crucial in proper water care. Some aquariums will need water changes every one to two days. Others are fine with just once per week. After cycling your aquarium and adding fish, determine how often you should do partial water changes by testing your water every day for the first few weeks. When the nitrate levels get close to 40 ppm for planted tanks or 20 ppm for bare, do a water change of 25-50%.
Feeding and Nutrition
One main issue for new Discus owners is what to feed them. First, even full-grown Discus fish have tiny mouths, so be sure their food is small enough to fit. If you see your fish seeming to eat food and spit it out repeatedly, you’ve given them too large of pieces.
The key to growing and keeping healthy Discus is to give them a varied diet. They need a variety of food to get the protein, vitamins, and minerals they require. In the wild, Discus are omnivores, scavenging the river bottom for algae and other plant matter. About a third of their diet comes from invertebrates such as small crustaceans and worms, so they must receive a similar diet in the home aquarium. Feed your Discus flake and pellet food that is specifically designed for them. For them to display their best colors, add meaty, frozen foods such as bloodworms, brine shrimp, and mysis shrimp. Many Discus keepers commonly feed beef heart. While some denounce this practice as unnatural, it does no harm and gives valuable protein to picky eaters.
While they love live foods, care should be taken when adding it to your aquarium. Adding live animals of any kind into your tank can introduce bacteria, parasites, and other harmful substances. So, if using live food, be sure only to add what your Discus can eat in two to three minutes. Additionally, Discus absolutely love live bloodworms. While it is fine for an occasional treat, Discus can become obsessed with them and refuse other food if given too often.
Discus fish are beautiful fish that are sure to be a topic of conversation, color, and activity in your home. While they require a little more attention than more common freshwater fish, they are well worth the effort. Be sure to have a proper environment for them, keep a strict tank maintenance schedule, and feed them a varied diet. If you keep these things in mind, you’ll be an expert Discus keeper in no time! For more information, check out our Complete Guide to Discus Fish Care.