Discus are considered the kings of the aquarium, the ultimate freshwater fish. I personally would say that title should go to freshwater stingrays, but discus are undoubtedly some of the most amazing fish you can have.
The problem with discus is there is a ton of information out there, it is very conflicting, and I don’t agree with some of it.
First, some of the information in this article will ruffle the feathers of some hardcore discus people. I am not going to just repeat what they say and I will argue directly against some of it. This will cause this article to get blown off instantly by those sorts of discus people. That is one reason I haven’t made a point to write this particular article before.
Schooling
Yes, discus are schooling fish. Although cichlids, they do naturally school, especially when younger. Usually, if you see a lone pair it is an actual mated pair at which point they are most concerned with each other more than the whole school. True mated pairs are what you might see a breeder keep alone in a 29. Like all schools, they should have a group of at least 6. You may start with a group of 6 or more, let a pair develop naturally, then isolate them for breeding.
Water
Discus like acidic water and they like it warm. In general, discus should be somewhere in the 82-84F range, but I have seen them very happy in 86-88F. They do like it acidic, but water quality is much more important than exact parameters. I have seen breeders keep them in a pH anywhere from 4.5 to 7.6. Yes, I did say 4.5! (Talk about asking for a pH crash.)
You do NOT have to use reverse osmosis (RO) water unless you have unusually alkaline or low-quality tap water, and even then I personally wouldn’t do all RO, I would something along the lines of half RO half tap. This will preserve the good stuff in the tap (helps maintain hardness and prevent pH crashes) while very effectively diluting the bad stuff (excessive hardness, nitrate, etc.).
Whenever possible stick to tap water. This keeps your fish used to something ‘normal’, allows stable water chemistry, easier water changes, and if you are breeding it allows you to sell to people doing the same and not have your fish crash on them.
Water Changes
Water changes are one of two topics of discus care most likely to ruffle feathers. People do anything from 20% per week to 90% 2x daily. I think 20% weekly on any aquarium is too low. Even a lightly stocked planted tank should get the bare minimum of 25% weekly. The lowest I have seen breeding discus get (so you know they are actually in good condition and not just ‘my discus is alive with x% water changes’) is 50% weekly. This is my standard for any freshwater tank.
Juvenile fish should get more. They like to eat a lot and while growing need even better water to prevent growth inhibiting hormones and other things that lower water quality from building up which can stunt them. This is true of any fish. This exact same concept should be applied to growing out Oscars, African cichlids, goldfish, and everything else. This is where I kind of leave it up to you. I would do AT LEAST 2x weekly 50%+ water changes, but if you can do them every 1-3 days that’s even better. More often is better. I am not going to be the discus nazi police and yell at you because you don’t do them every day. If you have the time and want to, go for it. If not, don’t beat yourself up over it.
I think this brings up a very important issue. Why do more for one fish than for another? Why do 50% weekly on discus and not on community fish or any other tank? Any other tank will also benefit from bigger and more frequent water changes. Any fish will get bigger, have better colors, stay healthier, and be more likely to breed and breed better if given better water. I am not saying you should start doing 75% daily or you are neglecting your fish, I just find it odd that some people are so rabid about discus water quality when all fish would do better with the exact same care. The only real difference is that discus are less forgiving of it. They don’t hide the damage as well as other fish. They go down hill more and faster if neglected compared to hardier fish. So a stunted tetra or cichlid is also severely harmed by the same inadequate water changes, they just don’t outright die after 6 months (it stretches out to two years instead of 8 years for example, but because it was two years we convince ourselves it wasn’t our care during that time). Ideally we all have an unlimited supply of dechlorinated water of the right temp and we could setup systems that constantly filled with freshwater, recirculating mainly to keep flow up. Treat ALL your fish like discus. They will all thrive like you have never seen before.
Tankmates
How you decide to keep your discus will dictate what all else can go along with them. The most common and best options for tankmates are cardinal tetras, rummynose tetras, sterbai cories, bristlenose plecoes, and fancy plecoes such as gold nugget, royal, etc. There are tons of other options including: most tetras (emperor, congo, serpae, black phantom, bloodfin, hatchets, glowlight, gold, black neon, bleeding heart, etc.), barbs (cherry, gold, checkerboard, odessa, rosey, etc.), most cories (peppered, panda, julii, etc.), many loaches (yoyo, angelicus, kubotai, clown, zebra, etc.), ram and other dwarf cichlids, harlequin rasboras, Siamese algae eaters, and others. Keep in mind many of these fish are only compatible at the low end of the temperature range for discus, so if you keep them pretty warm you will not be able to consider most of these fish. You also want to avoid small torpedo shaped tetras, especially young ones with larger discus. This means you probably don’t want to do neon tetras. You may not want to add young, small cardinals to a tank with larger discus in it. These fish just fit to easily in a discus mouth. You want to avoid predatory fish like certain catfish, arowanas, stingrays, etc. You also want to avoid anything nippy or willing to chew (some plecoes, tiger barbs, many livebearers, etc.). Keep in mind that the further you go from the ‘standard’ tankmates the more likely you will have issues with nipping, aggression, etc. If you decide to stray from the standards just be extra cautious and when in doubt move them out, hopefully just to another tank. For accurate info on the wild parameters of fish to see if they will work well with discus check FishBase.org. It is used and maintained by scientists so it isn’t just another hobbyist site full of misinformation and opinions.
Angels introducing parasites to discus isn’t a concern to me, parasites are a concern with any species and discus are certainly capable of bringing in parasites to other discus. So should you not even keep discus with discus? Of course not.
I want to make a point to emphasize that discus are NOT from some isolated hot watered, super acidic lake somewhere that doesn’t house any other fish. These fish are from the Amazon, you know, the place with tons and tons of other aquarium fish that we DON’T keep in such extreme conditions (including invasive pond goldfish). So how we got from that to the way some people treat them now is beyond me.
Substrate
Sand. A substrate is a natural part of any aquatic habitat. Sand is just as easy to keep clean as bare bottom. Discus naturally shoot water at the substrate hoping to stir up a little snack. They should have sand. For more information about sand please read the article: Sand as a Superior Substrate.
Bare bottom tanks are used when breeding and raising offspring. People like bare bottom because it allows them to get in and vacuum out every little half morsel that wasn’t eaten in the first five minutes so it doesn’t begin to rot and lower the almighty water quality. I understand the sentiment, and if you are going to do bare bottom it better be under these conditions, not a general display tank.
Feeding
This is the biggest issue. Feeding always brings out a strong reaction in hardcore discus people. They will tell you to feed only high protein meaty foods such as beefheart and other frozen foods, maybe mix in a little high-quality pellets in the rotation. I have even seen some say to feed only the high protein stuff and to NOT feed any type of flake or pellet. I think not feeding high-quality pellets is just plain wrong. In my experience, any fish (discus, stingrays, freshwater, saltwater, etc.) will do better with high-quality pellets (New Life Spectrum) as the only or at least main part of their diet. Discus people will argue against this until the end of time, or outright dismiss it. However, I can guarantee you that neither they, nor any of the people they talk to on hardcore discus forums have ever tried feeding New Life Spectrum exclusively for at least 6 months. Maybe they tried adding it to their rotation. Maybe they even tried it exclusively for a couple of weeks or even months, but I guarantee you none have given it a genuine chance to allow their fish to thrive. So although I have a lot of respect for them, they take excellent care of their fish, I just can’t blindly take it as fact that discus can’t thrive on New Life Spectrum exclusively from people who have never tried it. I have had discus grow well and even breed on New Life Spectrum.
If you just can’t bring yourself to feed only New Life Spectrum, okay, add some very high quality foods to the rotation. The only other pellet I would consider is New Era fish food. They seem to have some really good foods and if anyone is going to be a threat to New Life Spectrum it is them. As for frozen foods if you really want to use them as part of the diet make sure the pellets are the staple and add mysis shrimp (P.E. mysis are best), brine shrimp (go ahead and use the spirulina brine if it is available, and no, they are not just roughage), bloodworms, and maybe some beefheart (just don’t go crazy with it please).
The main argument is that if you feed like hardcore discus people do you will get the ‘best’ growth, proportions, etc. To me, if the only way to get a fish to that extreme of a condition is to feed like this then it sounds too much like bodybuilders. If the only way to get a human to certain physical condition is to feed him a certain way and work him out to an extreme, is it actually that healthy? I think the way some people are with discus is the same. If you have to go to that extreme to get those results (extreme feeding and water quality) then is it actually natural for them to be in that condition? Just because it is the extreme of possible, does that mean it is definitely ideal? I don’t think so. In fact, many if not most of the pictures I have seen of wild discus do NOT have the same proportions strived for by hardcore discus people. They have ‘big’ eyes and a body shape that if it were on a hobbyist’s discus they would get yelled out on a forum for stunting their fish. If a hardcore discus person looks at one of my fish and says, “The eyes are a little big in proportion to its body.” and that’s the only negative thing anyone can say about them, I’m okay with that. I can enjoy my fish. I can enjoy nice discus, even if they aren’t perfect. I don’t want to train myself to enjoy fewer fish.
Where to Get Discus
The fish pictured at the top of the page was picked up from a local wholesaler. This is my personal favorite discus. I think the color and pattern are both outstanding. I have gotten almost all my discus through the same route as all aquarium fish, through wholesalers who get them from fish farms. To me, I like knowing that if my discus was raised on a farm, shipped to a wholesaler, made it into a local store, and still settled in well and looks good (often in contrast to his buddies) I know he is hardy and will do very well in my tanks or my clients’ tanks. This is in contrast to the pampered discus raised by breeders who haven’t even heard the words ‘low water quality’. I think those discus are best compared to the preppy sheltered kid who may suddenly find himself in public school. The other kids who thrive in adverse conditions thrive while the pampered kid struggles. I have seen discus from good breeders go into people’s tanks and quickly start going downhill because, although well cared for, the discus simply weren’t used to such relatively low-quality conditions (which really should be very acceptable standards).
Peppering is black dotting on the fish. There is nothing wrong with peppering. Many discus people look down on peppering, especially in certain breeds. But it harms the fish in no way whatsoever. If you like it, don’t mind it, or come across an individual that you like and just happens to have peppering, buy it. Don’t let arbitrary made-up standards (even if commonly accepted) stop you from enjoying the fish you enjoy.
Tank Setup and Decor
Discus want a big tank, at least 55 but much larger is much better. A larger system will be much more stable chemically and less likely to have issues. Decor can be anything from a dimly lit (something like a 24″ light on a 48″ tank) with large pieces of driftwood, to an exceptionally well lit high tech planted tank. They do like driftwood and I would consider it a must. Tall, narrow pieces that simulate submerged tree roots are ideal. Live or fake plants are up to you. Rocks shouldn’t be excessive, but some accents are fine.
As stated before, the substrate should be sand unless you are actually breeding a true pair or raising their offspring. Other than that you aren’t needing a sterile hospital environment of a tank. You need a tank that makes them feel comfortable and happy. That is what sand and the other decor will do.