Beginner's Guide to Getting Started with Discus

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AC Members
Jun 22, 2010
Surrey, B.C. Canada (Vancouver)
Real Name
Greetings everyone,

I've only been an AC member for over a year, but have been fish-keeping, on and off, both fresh and saltwater, for over 50 years, since I was a kid. While a teenager, I bred quite a number of varieties of fish, Angels, Tetras, Danios, Barbs, Gouramis & Bettas, among others. In the nineteen fifties LFS's would give me a nickel or a dime for 3 month old fry. My, times have sure changed !

Anyway, my main hobby love over the past few years (and prior to that as well) has been Discus, and while researching various forums I found that there really wasn't a single Sticky or other thread that provided a reasonably comprehensive, step by step guide to getting started with these beautiful fish, in my view anyway, so I decided to write one myself to try and help out those folks who wanted to try discus-keeping.

My illustrated guide was posted as a Sticky in the forum, but since I spend a lot of time on AC as well, and noticed there were quite of number of current interested discus-keepers on AC, and wannabees as well, I offered the Guide to this forum.

So with Debbi Pinkerton's and Bob Bishop's acquiescence & help, the Guide is attached for you to have a read through. Hopefully it will give you the necessary grounding to feel confident about launching yourself into raising these marvelous fish !

Best of luck to you all.



Family: Cichlidae

Genus: Symphysodon

1. S. Discus Heckel 2. S.Aequifasciatus (green discus) 3. S. Haraldi (blue and brown)

Wild discus originate from a number of tributaries of the Amazon River inSouth America. They usually live inlarge social groups in shallow river,stream, or creek beds of slow-moving, soft water near the banks where tree roots protrude, providing cover. The water temperature is generally constant in the low 80’s Fahrenheit, and the pH is acidic, well below 7.0 neutrality. The water is very soft as it contains very small amounts of dissolved minerals. These conditions differ significantly from the environment usually found in home aquaria but the discus have adapted well. For instance, domestic discus have shown they are able to thrive in steady but wide-ranging pH levels, from 5.0, to up to 8.0. They have also done well under stronger lighting conditions, and in heavily planted environments. However, all discus remain largely intolerant of poor water quality, or water temperatures below 82 F.

There was very little known or written about discus until after the middle part of the 20th century, and it wasn’t until around the 1960s that hobbyists in various parts of the world began breeding wild-caught discus. After that time, a good deal of information began to emerge about keeping and breeding these marvelous fish. In the 1970s and 80s, there was a proliferation of breeders who established discus fish farms for local and export sale, mainly in South East Asia and some parts of Europe, particularly in Germany. By 1990, many new and colorful varieties of this intriguing fish had been developed, and the hobby was in full bloom in North America.

Discus are one of the most graceful, interesting, and arguably the most beautiful of all freshwater tropical fish. The fascination of keeping and raising these magnificent fish has taken the aquatics world by storm, and you’re one of the many wanting to get started with this very satisfying hobby.

This guide is intended to get youstarted on the right footing – to enable you to raise the “King of theAquarium” in good health, with the least amount of start-up snags and problems.

Here’s how to get started !


Discus are relatively large fish, growing to 6 inches or more at maturity, measured from nose to tip of tail, and therefore require a good deal of tank space in order to reach their potential and thrive. I recommend you start off with the largest tank you can afford. This should be no less than 55 gallons, but more preferably in the 65 to 75 gallon range. If budget is a problem, buy a used tank. There are many to be found on Craig’s List.


1) Heating

Discus require a temperature range of 82 to 86 degrees Fahrenheit in order to thrive. You’ll need to acquire a heater of sufficient wattage to maintain the desirable temperature for keeping your discus, in accord with the size of your tank. As a guide, 4 or 5 watts per gallon should be sufficient– so a 250 watt heater should do nicely in a 55 gallon tank. Many heaters only have a maximum temperature setting of 86 Fahrenheit, and since your room temperature will very likely be much lower than that through most of the year, it will be very difficult for such a heater to achieve and constantly maintain water temperature at the maximum setting level, particularly if your tank is uncovered or partially uncovered. So it’s best to get a heater with a maximum setting level of 93 Fahrenheit. There are a number of reliable makes on the market, so you will have a good selection to choose from.

2) Filtration

There are three types of filtration, i.e. biological, mechanical and chemical.

1- Biological filtration refers to the breakdown of toxic ammonia and nitrites,and then into nitrates by a colony of bacteria. These bacteria are often referred to as ‘beneficial’, or ‘nitrifying’ bacteria.

2- Mechanical filtration refers to the process of removing solid waste matter and other particulates from the water column. Examples include foam pads and flosses.

3- Chemical filtration removes chemical impurities and discolorations and clarifies the water. Carbon is often used for this purpose.

All three types of filtration can be maintained, or ‘housed’ if you will, in the actual filter container types that you select for your tank, whether that be a Hang-On-Back (HOB), or canister. A sponge filter will provide for biological and some mechanical filtration. Your colony of beneficial bacteria will establish itself in or on tank surfaces, but primarily on and within what everfilter media you elect to use in your filtration container(s).

There are many reliable types of filters to choose from. Many,if not most, discus keepers raise their fish in bare-bottom tanks and they usually employ one or more sponge filters, often supplemented by either HOBs or canister filters, to provide for all their filtration needs. In a planted tank, the preference seems to be to use either HOBs, or canisters, or both together, and to forego sponge filtration, primarily for aesthetic purposes.

The size of the tank, its purpose, and your preference will determine the needed type, size and capacity of the various filters which are available to choose from. Capacity is measured by the volume of water turned over each hour. A complete turnover of at least four times an hour is suggested as being suitable. An example of adequate filter capacity for a 55 gallon tank would be to use a filter rated for tanks up to 70 or 80 gallons, and which has an average water flow rate of 200 or more gallons per hour. This will result in a complete water turnover rate in the tank of approximately four times an hour.

3) Test Kits and Other Essentials

One of the most important items of equipment you will need are test kits to test your water on a regular basis for the presence of ammonia, nitrites, and nitrates, and to determine the pH, and general and carbonate hardness levels.

While your local fishstore (LFS) will very likely provide a water testing service at no cost to you, this can be quite inconvenient. With your own test kits, you will be able to quickly check your water parameters at any time. This will allow you to ensure your ongoing tank care is being maintained as it should, and to determine if your water is the culprit should problems occur.

Once your tank is fully cycled and ready to house fish, the test for both ammonia and nitrites should read “0”, and nitrates should be less than 20 milligrams per liter (mg/L). Your pH test should reflect a steady, stable maintenance of pH anywhere between 6.0 and 8.0. For discus-keeping, your water’s General Hardness (GH) can suitably be anywhere between a low of “0” to a high of 200 mg/L, whereas Carbonate Hardness(KH) should generally be between 40 and 100 mg/L.

You will also want to equip yourself with other essential items, such as a water conditioner to remove chlorines, chloramines and other undesirable elements from your tapwater. A water conditioner should be used at start-up when cycling your tank, and whenever replacing water during water changes.

Other needed items are a thermometer, fish net, siphon hose, five gallon bucket or pail for waterchanges, sponge, scrub brush, perhaps a water barrel for ageing water (a food-safe garbage pail will do), extra filter media items such as filter floss, foam pads, etc. and of course, some fish foods. If you’re doing a planted tank, you’ll need substrate, plants, driftwood and/or rocks, etc.

Once you have decided on the size of your tank, you’ll need a sturdy stand to carry the weight. A filled tank, with substrate, driftwood, etc., will average around 10 lbs. per gallon, so a 55 gallon tank will weigh over a quarter of a ton. Buy a ready-made stand that is specifically designed to maintain the weight of the type and size of tank you are getting or, if you are going a home-made route, get some expert help to ensure it is properly braced and structured to accommodate the weight.

As for lighting, you won’t need extra strong, bright lighting for discus. Low light will do, perhaps in the range of around one to two watts per gallon. For a planted tank, this should prove adequate for many, if not most, of the hardy, easy to grow plants that will also tolerate the higher temperature you will be maintaining for your discus.


1. Bare-Bottom Tank

This set-up is by far the most preferred approach by both newcomers to the hobby and experienced aquarists alike, for “growing-out” juvenile discus or for keeping adults. It is generally regarded as the easiest for maintenance reasons, and the most successful way of keeping discus. It allows you to readily spot any build-up of uneaten food, fish feces, or other matter, and quickly siphon it off at anytime. It makes it easier to undertake more frequent and larger water changes to promote better and quicker growth of juveniles, to maintain a high level of water quality at all times, and to more easily clean tank glass, as well as to service or change equipment. A bare bottom tank is easier to medicate if that should ever prove necessary.

2. Planted/Display Tank

This second option can be either discus only, or a “community” type tank with some other species offish. For the hobbyist, there is arguably nothing more attractive than a well aquascaped discus display tank. It’s a sight to behold and could suit you well, particularly if you have previous experience keeping tropical fish in a planted tank environment.

The ratio of fish to size of tank will be reduced in this set-up, given the quantity of water taken up by substrate, plants and other décor. In this case you’ll want to either increase the size of your tank, or reduce the number of fish you’ll be keeping. For example, if you were planning to keep eight adults in a 75 gallon bare- bottom tank, you should reduce that number to six in the same-sized planted tank.

Secondly, for your discus’ sake your water temperature will need to be maintained at no less than82 F – nothing lower will do – and that can pose a challenge for keeping plants, as many varieties do not do well at that temperature and above. Planted discus tanks entail more work and attention to keeping both elements healthy and thriving. Your focus will obviously have to be on the discus.
So, if you have no prior experience with a planted aquarium, you would be well-advised to go for a bare-bottom set-up, at least until you gain experience with discus. However, if you do have experience with planted tanks, you needn’t be fearful of giving it ago if you accept the challenge of the extra attention and diligence needed. It’s certain you will find it most satisfying and enjoyable.


You have made your decision as to the size of tank and type of set-up you want, and you’ve bought the tank, stand,lighting, and the other necessary pieces of equipment. The tank has been set up in it’s permanent location in the room, you have readied the filter, or filters, for operation,and you have placed the heater in the position you want it. If doing a planted tank, you have also added your selection of rinsed substrate, driftwood, or any other décor, and put your desired arrangement of plants in place in the substrate. As a last step before plugging in and starting the filters and the heater, you have filled the tank, at least to a 90 % level, with conditioned warm tap water of at least 82 F.
It is now important to ensure the tank is cycled. NEVER, never introduce discus to an uncycled, or cycling tank. It can, and probably will, kill them. It’s cruel and expensive ! ‘Cycling’ can probably best be described as the growth of colonies of beneficial types of bacteria, called nitrifying bacteria. They are necessary because they neutralize ammonia, convert it into nitrites, and finally render the nitrites to produce nitrates. Ammonia and nitrites are toxic to fish, whereas nitrates are much less toxic, and generally harmless in moderately low concentrations. When you cycle a tank, you are really cycling the filter materials, or media. While there will be some bacterial presence on the tank glass walls, on driftwood or other decor, and in and on substrate, a majority of the bacteria will likely be in the filter(s), although a good amount may be located in the substrate. Colonies of beneficial bacteria can only develop and survive in the presence of ammonia. In a cycled aquarium, these bacteria will maintain themselves insufficient quantities to render harmless all the ammonia that is being produced in the tank by the fish , and by decaying plant matter, uneaten decaying fishfood, etc.

Fresh water from the tap has very little or no ammonia and no beneficial bacteria. One of the more accepted methods of starting the cycling process, called the fishless method, is to begin introducing store-bought ammonia (NH3) to a newly water filled tank. Bottled ammonia is readily available inapproximately 10% concentration with only water added. Read the label. It should contain only ammonia and water - no dyes, fragrances, nor surfactants. It should be colorless and should not produce any foam when shaken. You can buy this ammonia at most discount or chain grocery stores or hardware stores.

With the filter on and the heater running, add sufficient ammonia to your tank to produce an ammonia test reading of 4 or 5 ppm. Start by adding one teaspoon of ammonia for every ten gallons of water, or five teaspoons in a 55 gallon tank. Swirl it around and let it sit. Please note that ammonia at the dosage level suggested above is the quantity needed when using a 10 % concentration of ammonia in water. If you’re using 100% pure ammonia, the dosage will need to be reduced accordingly, i.e., by 10 times, - only six to eight drops of ammonia per 10 gallons.

Test the ammonia level and add more ammonia if necessary, a half teaspoon or so at a time, until a test shows a reading of 4 or 5 ppm. Then test daily or every second day until the ammonia level has dropped to around 2 ppm. This indicates that bacteria have begun to develop and neutralize the ammonia. Test for nitrites at this point; you should get a reading indicating that nitrites are present. Add more ammonia, a teaspoon or two at a time, to bring the level back up to 4 or 5 ppm, in order to maintain sufficient ammonia in your tank for the growing bacterial colony to consume and survive. Keep testing for ammonia and nitrites daily, or every second day, while at the same time adding ammonia regularly until the nitrites have spiked up to a high reading. It will take a few more days for a high nitrite level to drop to a low range, as the type of nitrifying bacteria that renders nitrites into nitrates take somewhat longer to grow and multiply.

Over time, when your testing regularly reads a ‘0’ level for both ammonia and nitrites anywhere from 12 to 24 hours after you have added your last dose of ammonia, you will know that the bacteria levels have developed in sufficient quantity to deal with the ammonia in the tank. At this stage, the nitrates level will be high. Do a large water change of75% or more to reduce the nitrates to 20 ppm or less. Your tank has now fully cycled and is ready for fish. Remember, you need to keep adding ammonia in small amounts every day or so while your tank is cycling and the bacteria colonies are growing, so the bacteria colonies will not die off, until you are ready to add fish to the tank.

This process can take from three to six weeks, but this method will usually accomplish it in around three weeks. This can be speeded up if you add some colonized material from an established, mature and healthy tank, such as a small quantity of substrate placed in a tied-up nylon bag, or if you add a seasoned filter media, like a foam pad.

One final note, if you’ve opted to begin with a planted tank, consider allowing some further time following the cycle to acclimate and start your plants’ growth before introducing the discus. A total cycling and seasoning period of 45 to 60 days should allow the plants sufficient time to become established.

The entire cycling process can be eliminated if you can buy a cycled sponge from the discus supplier, or add aseasoned, colonized filter with all of its media intact from an established healthy tank to your new tank. In this case, fish can be added immediately. If you do so, test your water daily for the first few days to ensure there is no ammonia or nitrites. This is to confirm that the size of the bacterial colony you have introduced is sufficient to deal with the fish bio-load you have placed in your tank. If you add cycled media it should come from the fish supplier or from another tank you have, not another source like a friend or the LFS.


Discus are tougher than a lot of people think and they can be relatively easy to raise and keep healthy if one ‘follows the rules’. Perhaps the most important of these rules is maintaining water quality at a high level. Discus are more demanding, or shall we say, more intolerant in this area, than almost all other types of tropical freshwater fish. Here are the conditions that need to be maintained on a consistent basis.

A – Conditioning Your Tap Water

Conditioning means removing, or neutralizing, those elements in your tap water that can be toxic to fish –mainly chlorine, chloramines and other harmful elements. There are many effective water conditioners on the market. Follow the dosage directions on the container to condition tap water for your initial tank set-upand for all the water used for water changes.

B – Ph Stability (Range of Acidity or Alkalinity)

The vast majority of discus available today are farm-bred and raised, and can readily tolerate, if not thrive in, pH levels ranging from 6.0 to 8.0. Many of you will find that the pH of your tap water is in the 6.5 to 7.5 range, which is perfectly acceptable.

The key to pH is to maintain a steady, relatively consistent level at all times. Even moderate fluctuations in pH, if occurring quickly, can be harmful,i f not fatal, to your fish. This is why it is recommended that beginners not attempt to modify or alter pH levels byusing chemicals. If the pH of your water is 7.7, then stick with that. Resist the temptation to change it!

The first step is to test the water coming straight out of your tap. Then, fill a five gallon bucket with tap water. Let the water sit and ‘age’, aerated, for a 24 hour period and test it again. Tap water often contains a lot of dissolved carbon dioxide. When water is released, the carbon dioxide dissipates and the pH then rises. If the pH rises by no more than 0.3 or 0.4, then it should be safe for you to use water directly out of the tap for your water changes, or for topping up evaporated water if necessary, so long as that water is conditioned to remove chlorine,etc., and the temperature is within a degree or two of that in your tank. If the pH rises by more than this, then the water needs to be aged before doing your water changes. Otherwise, your fish can experience dangerous, or fatal, pH shock. Many aquarists maintain water ageing barrels of various sizes, usually in the range of 40 to 50 gallons or more to accommodate their water changes, thus ensuring stability of their pH. Ageing barrels are most often simply inexpensive food-safe garbage pails in which aquarists store, aerate and heat their conditioned water before doing water changes. Ageing also ensures the conditioner (or dechlorinator) has had ample time to work. The length of time needed to age the water varies, and it depends on how long it takes to gas off the carbon dioxide. If the pH in the barrel does not rise further after 12 hours, for example, then the water should be aged 12 or more hours.

C – Water Changes (WC’s)

Frequent water changes are of singularimportance for maintaining good water quality and chemistry – it’s the key tothriving, healthy discus. If raisingjuvies, your ideal routine would be daily wc’s of between at least 25%, to 50%or more. In a smaller tank, you can usea siphon hose and bucket, but may want a hose with attached pump for largertanks to move the water from the tank to the chosen drain outlet, and from theageing barrel, if needed, to the tank.

Many discus-keepers do well with wc’sof 50% or more every second or third day, while others keep healthy and happydiscus with large, twice-weekly wc’s, ensuring fecal matter and uneaten food is siphoned off regularly as itaccumulates. The efficacy of yourfiltration will also play a part in deciding on the frequency and quantity ofyour wc’s. In a display tank, yourplants will assist filtration to some extent by consuming, orutilizing, some wastes, and will help keep nitrate levels lower. However, the other side of the equation isthat planted tanks are a great deal more difficult to keep clean and spotlessthan a bare-bottom. Substrate, in particular, harbors a lot of waste and otherundesirable matter that even regular vacuuming will not fully remove.

D– GeneralMaintenance (Overall TankCleanliness)

In addition to consistentlymaintaining good water chemistry via your wc’s, you will need to incorporatesome other maintenance items in your daily, every second day, semi-weekly, orweekly routines. Wipe down the insidewalls of your tank when doing wc’s in order to remove algae and discus’ sheddedslime coating, which film onto the glass. If your tank is planted, you will need to regularly vacuum yoursubstrate. Semi-weekly or weekly mightbe enough, but some do it with each wc if not more frequently than that.

If you are using HOB filters, yourfilter media should be rinsed on a regular basis, no less than weekly, butbetter still, semi-weekly. Rinse thefilter media in the tank water after it has been pumped out, or in conditionedwarm tap water, so as to avoid destroying any significant amount of beneficialbacteria. If you were to concurrently rinse all, or most, of the media inuntreated tap water, for example, or discard most media items all at once forreplacement with new, (such as very dirty and deteriorating foam pads, sponges,filter floss, etc.) you would effectively be removing or destroying a very largeportion of your biological filtration system (the beneficial bacteria). Thiscould result in dangerous spikes of ammonia and nitrites. Change old,discard-ready media to new on a rotated basis, one filter at a time, and/or onemedia component at a time.

If you are using canister filter(s),discus keepers will usually rinse media and clean their filters on a lessfrequent basis, on average every second or third month. The use of pre-filters on their intakes,coupled with the size, power and efficiencyof these filters as opposed to HOB’s, will make this more extended cleansing routine adequate.


A – Ages, Sizes,and Appearance

If you’re thinking of growing outjuveniles, or ‘juvies’, ideally you’ll want to acquire three inch specimenswhich will likely be about four months old. As a general guide, six to eight or even ten fish of this size will dowell in a 55 gallon tank, at least until they approach maturity. At this point, you will do well to reduce thenumber to six or seven. Your secondoption is to go for larger, older specimens, near adult or adult of four to sixinches. You might like to see themdevelop into at least one mated pairing, for breeding. In this case, you’ll need to limit the numberto six or seven in a 55 gallon tank. As a novice to fish-keeping, you shouldthink carefully before buying very small discus less than two inches long(fry). They require more frequentfeedings and frequent large water changes, and they have a low tolerance forpoor water quality which generally leads to stunting.

Look for fish that have a round body(not oval or ‘football’-shaped), clear eyes, and a respiration rate with gillcover movement that is fairly slow and steady. Their fins should normally be outstretched,not clamped, and they should be eating well. The size of their eyes should appear to be in an attractive proportionto their body size. A stunted fish willhave unusually large eyes compared to the body, which will be somewhat evident.

When viewed head-on, the forehead, orbrow should not appear pinched in, nor should the stomach/lower body area belowthe head. In a solid colored fish, thecoloration should be bright, not extremely pale and washed-out looking. Avoid any discus that appear dark in color.

They should be active and appear comfortablewith their surroundings, not darting about and/or hiding. They should not shyaway from the front of the tank as you view them. Ask your livestock source to feed them and thenwatch to ensure they eat. Find out whatthey have been eating, how frequently, and the temperature and Ph of the waterthey have been kept in. Learn as much asyou can of their background so that you are well-equipped to keep themyourself.

B – Sources ofLivestock Purchases

Probably the most CRITICALLY IMPORTANTelement in successful discus-keeping is to buy your fish from a knowledgeable,experienced, reputable and fully reliable source. This is almost your guaranteeof getting great- looking, healthy fish .

There are, generally, three sourcesfor discus:

· Local Breeders ~ They will usually provide healthy fish, acclimated to localconditions. You will first need to obtain solid positive references to fullysatisfy yourself that the breeder sells healthy, quality fish. This route does of course support localbreeders, but the fish being sold generally tend to be very young. Reputable breeders understand that sales areoften by word-of-mouth and so they want to maintain a positive reputation.

· Importers ~ Like the breeders, reputableimporters strive to maintain a positive reputation. Again, get references. This source generally costs more than localbreeders, but the variety available is much better and the size bigger.

· LFS ~ This source is usually expensive.They are unwilling or unable to invest the time and money discus require. It would probably be non-profitable if theydid. The fish are often on a centralwater system, and so pick up illnesses from other fish. The quality, even ifhealthy, tends to be poor. This sourceis not recommended.

While some LFS sell healthy, qualitydiscus, most do not, so you would be well-advised to buy your fish from anexperienced long-term breeder or importer in or near your area. Many discus keepers acquire their stock fromwell-known sources of high quality discus, and have them air shipped to theirlocation. If and when doing this, it isimportant to ask for photos in advance, of the fish you will be buying. The delivered product should equate to thephotos you were given. Do your homeworkhere, and seriously consider getting your fish from one of several experiencedand reputable sponsors of the SimplyDiscus, The British and InternationalDiscus Keepers Association (BIDKA) or other forums. Check them out and make enquiries of otherforum members.


How many fish should you buy? Discus are social fish and have shown to bemost comfortable when kept in a group of five or more. They are generallypeaceful, but being cichlids, they are prone to somewhat aggressive behaviortoward their own kind . They will almostalways develop a “pecking order” – quite normal behavior for discus. While thissomewhat “bullying” behavior can be quite stressful to those being picked on,it is rarely physically harmful in a group of this size. Discus rarely show aggression towards otherfish. Keeping fewer fish than suggestedabove will often result in one or two being bullied to an undesirable extent bythe dominant one as the pecking order is established. So, there is safety andsecurity in numbers.

The generally accepted ‘rule of thumb’is to keep no more than one adult fish per 10 gallons of water, or five or sixadult fish in a 55 gallon tank. If raising juvies, double the number of fishshould do well in the same-sized tank until they grow out to 4 inches and over.Then you will have to consider downsizing your group of fish, getting a larger tank for them, or gettinganother tank and splitting the group.

Overstocking is never a good idea. Itcan be stressful on the fish, and it ties the hobbyist to his or her tank. One can’t miss a wc, and one is completelydependent on a never-fail source of power.


There are a number of types of fishwhich are compatible with discus, and which are more or less tolerant of thehigher discus tank temperature. Avoid smaller fish which could become ‘lunch’for discus, or fast-moving fish such as zebra danios which can make themnervous. Some fish are “nippers” and areto be avoided, such as tiger barbs. Manyfish cannot tolerate discus temperatures.

Examples of generally good discus tankmates include some species of tetras such as Cardinals, Rummy-noses,Glow-lights, and Lemon tetras. Harlequinor Copper Rasboras and Hatchet fish are acceptable. Bushy-nosed Plecos and German Blue Rams arealso good tankmates. A number of bottomdwellers are good mates as well, such as sterbai, peppered, bronze, or emeraldCorydoras, to name a few. Dwarf or PearlGouramis should do fine as well, but not other strains of Gouramis which maytend to be overly aggressive and stress the discus, or outcompete them forfood.

A number of discus hobbyists havesuccessfully kept bettas, angel fish, guppies and some slow-moving, more peaceful barbs with discus.


A – Acclimatizing the Fish

There are two commonly used methodsfor releasing newly-purchased fish intothe home aquaria. One is often referred to as ‘drop and plop’, where the discusare simply removed from the bag and placed in the tank without any furtherprep. The following second method easesthe transition.

Once you get your newly-purchased fishhome, you should properly acclimatize them to the temperature and pH of yourtank water. This is a fairly simpleprocedure, taking no more than an hour or so from start to finish. This will limit stress and shock caused by achange in temperature or pH.

First, float the bag of fish in yourtank for 20 minutes to equalize the bag water temperature to the water in yourtank. Then open the bag and check the pHin both your tank and the fish bag to satisfy yourself that there is no widevariance. If the pH is approximatelysimilar, the fish can be added without further acclimation.

If however, there is a variance ofmore than 0.3 or 0.4 in the pH, then begin to add water from your tank into thebag, slowly and in small increments – 15% or so of the bag’s water volume eachtime, allowing five to ten minutes between each addition, until you haveapproximately doubled the volume of water initially contained in the bag. Finally, do not pour the water, with fish,directly into your tank, as the bag water will be polluted with fishwaste. Gently pour the water from thebag through a fish net into a bucket. Aseach fish slides into the net, pause your pouring and place the netted fishinto your tank.

As a slight alternative to thismethod, some people float the bags first, then place the fish and bag water in a bucket or other container. Then, using an air supply hose with a gangvalve, water is dripped from the tank into the bucket to double the volume overthe course of an hour or so, taking care that the water in the bucket does notoverly cool down. The fish are thennetted out and placed in the tank.

B – QuarantiningNew Fish

If you bought your fish from areliable source, your tank is cycled with no other fish in it, and you haveacclimatized your fish as above, then you may place your new fish directly intothe tank.

If you already have fish in your tank,you need to quarantine the new ones. Quarantining means completely isolating the new fish from all otherfish, in a separate tank specifically set up for this purpose, and preferablylocated in a separate room. Also, a heater, filter, hoses, bucket, thermometer,etc. should be set aside for use solely in the quarantine tank. Take care that water on the hands from thequarantine tank does not get into the other tank, and vice versa.

You need to do this as the new fishmay be harboring pathogens they are immune to, but the existing fish arenot. Also, the stress of the move maycause problems for the new fish, and you don’t want to transfer this to theexisting tank. Finally, if the existingdiscus harbor pathogens they are resistant to, but the new fish are not, thenone risks the potential loss of some new fish. Therefore, all new fish , whether purchased from the same source or not,should be quarantined.

A quarantine should be of four to six weeks duration. If all seems well inthe quarantine tank after three or four weeks, take one fish from the main tankand one fish from the quarantine tank, place them into a third tank andquarantine for a further two weeks. Ifthere is only one fish in the quarantine tank, the single fish from the maintank can be added to the one quarantinetank. This needs to be done in order tominimize the impact to only one fish if a problem develops. If problems do arise, either the new fish orthe existing fish need to be treated.

Alternatively you may opt, as manyhobbyists do, to use a single quarantine tank instead of two. Add one fish from your main tank to the newstock of fishes and observe them during the quarantine period. This approachmay prove riskier, in that if your original fish have something they areresistant to, but the new fish are not, then you risk infecting all of your newfish rather than only one. If this were to occur during this method ofquarantine, you would need to treat all of the fish, new and original. If theprevious method had been followed, only the original fish and the two fish inthe third tank would need to be treated.

A tank in the 10 to 30 gallon rangewill usually suffice as a suitable quarantine tank, keeping in mind the numberand size of the new fish being quarantined. Remember the ‘size of fish pergallon’ rules. Before using it, thistank should of course be cycled, filtered, and of the same temperature and pHas your main tank. This tank can alsoserve as a hospital tank for medicating sick fish.

C – Diet andNutrition

Your discus need to be fed a varied,healthy diet which provides them with sources of protein, minerals and vitaminsessential to their health and development.

Packaged frozen foods are excellentsources of most of the essential elements. Some examples are blood worms, mysis shrimp, krill, and brine shrimp, all of which are usually fortified with vitamins and minerals. Discus will usually, readily take a varietyof good quality flake foods and pellets. Many aquarists feed homemade foods totheir discus, often using recipes with beef heart. Some are heavy on protein, while otherscontain large percentages of vegetable matter. Four good recipes may be found @ Google’ing discus fish foodrecipes will provide many links.

A general guide is that the youngerthe fish, the more frequent the feedings should be. A juvenile discus of two and a half to threeinches should grow well with four to six feedings daily. Feed only small amounts each time, usuallyonly as much as your fish can consume in under five minutes. A four inch fish should be fed two to fourtimes a day, and an adult discus, once or twice daily.


When quarantine procedures are notfollowed and cross-contamination occurs, or the fish are experiencing stress,they can succumb to parasites, bacterial infections or funguses.

Causes of stress are many and varied,but the most common are:

· Poor water quality and conditions

· Poor diet

· Overcrowding

· Bullying

While most, if not all, discus harborsome form of parasites or other pathogens on or within their bodies (just asanimals and humans do), healthy discus’ immune systems are well able to dealwith this, keeping matters in check and non-troubling. When the immune systemis weakened and starts to break down, pathogens get the upper hand, causingpoor health.

A – Recognizing aProblem

If and when any of your fish ceasesacting normally and begins to behave in strange, unusual ways, it’s almostalways a sign that something has begun to go wrong. Examples of strange behavior includeisolating itself from the rest of the group and hiding a good deal of thetime. It may refuse to eat, face therear of the tank, display clamped fins, show a lack of color, or a very darkenedcolor, or rub itself on plants or driftwood. All of these behaviors are signs of distress in the fish.

B – How to Proceed

First, test your water for ammonia,nitrites, nitrates and pH. If your tests show any unusual abnormality, such asthe presence of ammonia or nitrites or a significant change, up or down, inyour normal pH level, immediately do a large water change. Check the pH of the w/c water before you dothe change, and then test your tank water again after the wc to see whatchanges have taken place in either ammonia, nitrite, nitrate or pH levels.

You might also consider raising thetemperature in your tank gradually up to 88 or 90 F. Many will say that a 90 F temperature is agreat ‘cure-all’ for many ailments in their early stages. However, if you suspect a bacterial infection,do not raise the temperature. Warmer temperatures encourage bacterialreproduction.

There is no need to panic. Stay calm, observe the characteristics ofyour tank and all your fishes’ behavior, and begin seeking the help of otherforum members by posting a thread, detailing all of your tank conditions. Explain the problem, outline thesymptoms, which meds you have alreadytried and the results, and state the tank size, age, number and size of fish,your wc regime, whether bare-bottom or other, temperature, pH, ammonia,nitrite, nitrate readings, and anything new you have recently added to yourtank.

You will get help from experienced discuskeepers on the Simply Discus, BIDKA, or other forums who will advise you on howto proceed.


This guide should have supplied youwith all of the step-by-step instructions necessary to properly launch you intosuccessful discus keeping. The sectionson cycling the tank, water conditioning, water changes, and quarantining, alongwith sources of your livestock purchases, are particularly important. You woulddo well to review them carefully, and ensure you have a good understanding ofwhat you will need to do. If you havequestions regarding any matters related in this guide, you should of course notbe shy about asking other fish forum members. The “search” button can be very useful in finding information.

It is sincerely hoped that after reading this,you will have cemented your decision to move ahead with plans to keepdiscus. If you make an honest effort toadhere to the principles set out in this guide, it is almost certain you willfind that the patience and dedication involved in discus-keeping will make foran extremely interesting and rewarding experience. You will soon see for yourself that discusare not only beautiful, but have the unique personalities to match!

Have fun with the hobby!


Website Links:


Au, **** – TrophyDiscus (Cichlid Press 2007)

Au, **** – Back toNature Guide to Discus (Aqualog Verlag GmbH)

Soh, Andrew – Discus:The Naked Truth (Andrew Soh Pub. 2005)

Soh, Andrew – Discus:problems and Solutions (Andrew Soh Pub. 2009)

Shulze, Eberhard –Discus Fish: The King of All Aquarium Fish (Discus Limited 1988)

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May 29, 2007
New Jersey
Real Name
Nice job Paul!:thumbsup:


AC Members
Jun 22, 2010
Surrey, B.C. Canada (Vancouver)
Real Name
Thanks for your help in getting the guide on AC Debbi, and many thanks to Bob Bishop for all his hard work in getting it posted. Would be nice if your programmers could arrange to insert the cover page with the credits, and the discus pics that I attached with the Guide, but hey, I'm not complaining - I can imagine the difficulties getting this done. I just hope the article helps out those new discus-keepers, or those wanting to give it a go !


AC Members
Jun 22, 2010
Surrey, B.C. Canada (Vancouver)
Real Name
For you interested discus-keepers, if you have any questions after reading the guide, please feel free to fire away.
PM me at any time, if you wish - I'll be very happy to help in any way I can.


AC Members
Jun 22, 2010
Surrey, B.C. Canada (Vancouver)
Real Name
While the AC programming people are figuring out how to add the Cover Page and Photos included with my guide, I'd like to take the liberty of giving credit to those who helped me out a great deal in bringing the guide to fruition:

The guide was:
Written by: myself of course - Paul Villeneuve (username- discuspaul on other forums)
Edited by: Martha Morris (username- mmorris on, and
Photos supplied courtesy of: myself, Martha Morris, and Patricia Husband (username - Second Hand Pat, on - Hopefully, you'll see the pics up soon.
Special thanks for assistance & fine-tuning the guide: Keith Perkins (username - CozyKeith, on

I'm very gratified that the guide now appears on 3 other forums - i.e. ; ; the, and is scheduled to soon appear on, and BIDKA (British & International Discus-keepers Assoc.)

Not wanting to blow my own horn, but I'm simply and sincerely very pleased that the guide will potentially reach a wide readership, helping many interested new discus-keepers, or wannabes, get off on the right foot, and avoid the many pitfalls that so many others of us, including myself, have experienced when getting started with this, arguably, the most beautiful fish in the freshwater aquatics kingdom.
If that sounds self-serving & trite, then I plead guilty.
However, I really do feel that Discus have gotten a bad rep over the years, for being a very difficult species to raise & keep healthy - but it just 'ain't' so, and I'd like to do my little bit in getting this perception turned around..
(Please excuse my rambling on - I'll try to behave better in future.)

Discus-keeping is certainly not the be all, and end all, but it seems that a lot of aquarists have wanted to give it a try, but were afraid to do so due to the many negatives being reported about the work and attention involved, and how delicate/susceptible to problems, they were.
It's just not that way - they're really quite tough, adaptable fish - do give them a try.
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AC Members
Jun 28, 2006
SF Bay area, CA
Paul, your guide is very helpful & comprehensive! Nice job! Discus keeping is much easier than 30+ years ago but still a challenge especially for novice fish keepers. Discus are more demanding than many tropical fish but like most, supply their needs, get good stock & go beyond the "minimum" & many people could keep these magnificent fish. I hope to do it again soon. (especially if Martha gets her sapphires going again...awesome fish! Miss you already Martha!)


AC Members
Jun 22, 2010
Surrey, B.C. Canada (Vancouver)
Real Name
Many thanks fishorama, for your vote of confidence.
BTW, lately Martha has been quietly doing some fine breeding and raising discus, and she'll soon have available some super Cobalts, and Turqs, and possibly others - don't know about Sapphires - but all I can say is she'll no doubt have excellent stock available - at very reasonable prices - and anyone getting some of them will be certain to have healthy, well-raised, properly-shaped discus !


AC Members
Jun 28, 2006
SF Bay area, CA
Martha was the very first "discus person" to reach out to me on SD. She's very giving of her time & expertise, I consider her a friend & hope her new house issues have been addressed, it's always something...I've gone east to west coast...still not ready for any fish let alone discus but I hope soon (ish)...


AC Members
Feb 15, 2012
Thank you for pointing me in this direction for the read. I want to know though, I didn't see anything here on "Show discus" which was described in one of my books. They're discus kept for display purposes only and not in large groups, if I kept two juvenile show discus in a tank with my electric blue rams, and tetras and I saw some glo-fish dannos that were really neat, until this summer when I up myself to a 75 gallon would that be alright? I know a bigger discus would be super uncomfortable, but if I have two little guys in there so they have time to mature and out grow the tank it wouldn't hurt so much would it? I have a 30 gal. Also, someone told me LED lighting is bad to try and have live plants in your aquarium because they don't induce enough real light to grow for your fish, do you have recommendations for aquarium plants that do not require actual light?