My Experiences with Discus - Part I
Their Selection and Keeping
by Peter Gallagher
First published in the Cichlid Circular, New South Wales Cichlid Society, Australia. May 1990
This article is not written by an expert with twenty years experience, nor is it merely a collection of previously published material collated into an article. This article is about my own experiences, methods of fish keeping and raising Discus from eggs to adults. Some of the information may not always be the same as found in Discus books, however these methods are what I practice and they work for me and they work right here in Sydney.
Are Discus fish for me?
You must ask yourself this question more so than for any other type of fish commonly found in aquaria. Discus have a reputation as being fussy eaters, prone to disease and difficult to keep. This is both true and false. Discus can be fussy: for example if you feed them frozen blood worms as their only food, they may accept this for sometime, then refuse to eat it. This can be avoided by variety in feeding.
Prone to disease?
Yes, if you never clean your tanks, don't do enough water changes and generally neglect your fish, they will get sick. On the other hand I have fish that have never been sick a day in their lives.
Difficult to keep?
Yes, more difficult than, say, a Convict Cichlid (Archocentrus nigrofasciatum), but well within most fishkeepers' ability, provided certain criteria are met.
Are Discus fish for me?
Well, if your life is so busy that you wouldn't have time to do fifteen minutes of maintenance each day and an hour or so every week, plus time to feed the fish, then the answer should be NO!. If you have time to spend and you are keen to be successful in keeping Discus, then the answer should be YES!, and you will have many pleasurable experiences in store.
Keeping or breeding
Assuming your answer to the previous question was YES!, then what is your aim? Keeping Discus in a display tank or breeding? This question doesn't need a definite answer like the previous question, but it is worth asking anyway. For me the answer was breeding and it wasn't until I had bred Discus and raised their fry to adults that I really kept Discus in a planted display tank. If keeping a display tank is your aim, then your job is a little easier, but no less pleasurable. If you wish to breed them, you must think of many factors, such as placement of your tanks, storing and conditioning water etc., and one very important virtue that you will need is... patience.
When purchasing Discus, whether from a shop or a private fishkeeper, it is important to be careful and selective. Purchase the number of fish, type and size that suit your requirements. My philosophy has always been that it costs just as much to feed and house bad fish as it does to keep good quality fish. By this I don't mean that you should keep Turquoise Discus and not keep Brown Discus. I am saying you should strive to keep nicely shaped, large and good quality fish, be they Browns, Cobalts, Turquoise or whatever. This is where shopping around and being selective is very important.
Size, quality and colour all relate to cost. Basically, you get what you pay for, or do you? When buying small fish you must trust the seller. This is where being careful comes in. Some shops may misrepresent what they are selling, however this is rare. More commonly they may not know what they are selling. Even with these problems this is still the best way to buy Discus.
So how many Discus should I buy? This depends on what your aim is. If you want your fish for display purposes, then the number depends on how big your tank is. If you are going to set up a 5' x 2' x 2' tank with good filtration, you can house eight to ten adult Discus, a few less if you are going to have catfish and tetras as well. The size of the fish you will buy will decide the number of fish you need. If you can afford adults, then buy your eight to ten fish, but buy them a few at a time, so as to not overload the tank. And quarantine all new arrivals before putting them in with the existing fish. If, like most of as, you can't afford to buy adult fish, then you can basically buy fish as babies or as juveniles. Babies (the body around the size of a 50 cent piece), are the cheapest way to buy your fish. At this size they don't show much colour and just look like Brown Discus, even if they are in fact Turquoise Discus. Don't worry if babies colour up very late, as some varieties don't colour until they are twelve months of age or later. If buying small fish, buy more than you need or want as adults. Don't expect to get eight to ten adults from the same number of babies. My experience has shown, that out of the ten babies you decided to grow up to adults, one will die, one or two won't grow very well, and two just don't make the grade. These findings are based on my strict feeding program and my fussy selecting of display fish. If your aim is different, then adjust your number of fish accordingly.
If you buy juvenile fish (tennis ball diameter size) they are half grown and some of the hard work has already been done for you. You have the advantage that by this age (around six months) they should be showing some adult colouration. So you can get an idea of what they may look like when they are fully grown. The disadvantage is that you will pay for the extra size probably one third to half the price of an adult as opposed to one eighth of the price as a baby.
If you intend to breed Discus, it is best to buy young fish and grow them up. Allow 6 to 7 fish to get one pair and 8 to 10 fish to get two pairs as it is better to have too many fish than not enough, especially when you spend 12 to 18 months raising them. And don't sell your "spare" fish until the pairs have proved themselves by raising fry.
What to look for
Whether it is your aim to raise up quality fish for breeding or display you must start with fish that will grow to adult size. When buying young fish or adults you must look for fish that are healthy and not stunted. Stunted fish should be avoided no matter how cheap they are.
So, what do I look for? Well, when looking at the health of fish, adults and juveniles should show good colour for their type. Regardless of age and size healthy fish should not be dark or have clamped fins or be hiding in the darkest corner of the tank. However, if the fish have just arrived in the shop they may suffer from these symptoms until they settle in.
Another sign to look for in healthy Discus is the head. When looking at the fish head-on, the area of the head from the eyes upwards should be convex not concave. This shows whether the fish has been eating well and if the fish has been using the food to build its body. If it is concave, it can show that the fish has internal parasites in its stomach. When I purchase a fish, I like to watch its behaviour in the tank. Normal behaviour to look for is alertness, breathing that is not too heavy (adults breathe around 60 to 80 times per minute at rest, babies a little more than this). Mild fighting amongst themselves is normal in a group of Discus, whether adult or juveniles. However, deliberate bullies damaging other fish should be avoided. Any sign of disease of other problems such as frayed fins or torn fins and skin blemishes etc. should also be assessed.
Equally important in discus is stunting. Like humans, discus grow fastest as babies and slow down during adolescence until they reach adulthood. In humans, adulthood is reached around eighteen years and after that time, if large amounts of food are consumed, height remains the same, but humans usually become obese. The same thing happens with Discus. They grow till they are around twenty months old and after that they will only fill out, but their diameter stays the same. This is also true for many other fish and other cichlids, however the adult age varies.
With this in mind, imagine a Discus that has been neglected as a baby and had not enough food at its most critical time. An example of this would be a fish of tennis ball size at sixteen months of age instead of six months of age (the expected size and age). A fish purchased like this would not grow very fast at that age and would never reach its potential adult size.
Tell-tale signs of stunting are large eyes in relation to the body size, and long bodies (length from nose to base of the tail is significantly greater than body height without fins). With this in mind you should look for small eyed, round bodied fish that are healthy in appearance. If these fish are found and they cost a little more than others, you can buy them knowing that you will be better off in the long run.
Colours and varieties
Unfortunately, there are few fish that have more confusion and misinformation than the naming of Discus varieties. The only information I can pass on here is in my opinion the following, even if this is unpopular amongst the aquarium trade. I am often asked if these fish are red turquoise, blue turquoise, green turquoise etc. Many of these fish could be housed in three different environments and truthfully described as any one of those three varieties. If I am asked what one of my fish is, I usually simply say, that the fish is a Turquoise Discus and not give a colourful adjective to try and make the fish sound better and more expensive.
Many shops, breeders and wholesalers describe fish to make them sound better, e.g. Gypsy Discus, Blue-Faced Discus, Pearl Discus, Checkerboard Discus, Power Blue Discus to name but a few. My advice is to be careful what you buy and how much you pay. If the fish is what you want and like, buy them, but don't buy some fish that has a prestigious name and price tag, but looks very ordinary. I once answered an advertisement in the paper for adult Discus for sale, and when I rang the owner of the fish told me that he had Gypsy Discus, Red Pearls and Wattley's Turquoise. When I arrived to look at the fish, the Gypsies were in my opinion Brown Discus. The Red Pearls, which are supposed to have turquoise spots on a red background, had stripes instead of spots and the Wattley's Turquoise was not what I know to be the Wattley's Turquoise (which happens to be my favourite variety). So this person was either misinformed by the person who sold him the fish as young ones or he had looked through a book and picked out a few good names to try and sell his fish. On the bright side there are some varieties that you can buy and they usually are labelled correctly.
Making their tank their home
Like all fish, Discus require favourable conditions, some will not grow and some will simply die "for no reason". It is this fact that has given Discus the "hard to keep" label. This need not be the case for you, provided certain conditions are met.
Discus require clean water. They are very intolerant of high levels of ammonia and nitrite, as well as large amounts of bacteria. For this reason large amounts of fish waste and uneaten food will not be tolerated by Discus. If you have decided like many others to keep your Discus in bare tanks (without gravel), then keeping the tank clean is much easier, because uneaten food and fish waste are easier to see and siphon off. If you have chosen to keep your Discus in a planted tank then it is still possible to keep the tank clean, but care must be taken. When feeding, try to avoid food that disperses across the whole tank quickly, before the fish can eat it. I use the cone shaped worm feeders for feeding frozen blood worms in my display tanks. However, some fish may need a few feeds of life tubifex worms in these feeders to become accustomed to using them. When feeding beef heart in my display tank, I break it up carefully and allow it to sink to the bottom in a sparsely planted area of the tank. This makes it easier to remove any uneaten food on the rare occasions when it is not all eaten. When feeding food that may cause a problem if left uneaten, such as beef heart, it is a good idea to feed it as the first meal in the morning, when the fish are most hungry, and if you feed it again that day, do so when you come home from work.
Feeding is a very important subject where Discus are concerned and I will go into more detail in subsequent articles on my experiences with Discus. However, the most important thing to remember is to feed a variety of foods and get used to the amounts your fish eat. I was once told: "It isn't the amount the fish eats that kills it, it is the amount of food it leaves behind." For this reason it is a good idea for one person to feed the fish and so get used to the fish's needs. Once you know the amount and times you are going to feed, then you can encourage someone else to relieve you and give occasional feeds. A word of warning: Discus are not the kind of fish you let young children feed.
Other precautions worth taking with a display tank are to add scavenger fish like catfish, such as Royal Whiptails, Whiptails, Corydoras, and smaller Plecostomus species (Royal, gibbiceps, clown) up to 8 inches. These fish clean up the bottom of the tank and can control algae. One note on catfish: some types, such as Royal Whiptails (Sturisoma panamenser) and Twig Catfish (Farlowella sp.) are not tolerant of low pH and will die once it falls below pH 5. So if you are trying to keep your water acid for Discus, you must keep a check on the pH regularly. Other good tank mates are tetras. However, quarantine all new fish before putting them in to your Discus tank. Why let a $1.50 tetra bring in a disease that will kill a $250 Discus? Some tetras I can recommend with Discus are Congo Tetras (Phenacogrammus interruptus), Cardinal Tetras (Pracheirodon axelrodti), but my favourite Tetras with Discus are the common Serpae Tetras (Hyphessobryon serpae), its red colouration is a good contrast to the green plants and the turquoise colour of the Discus.
As far as other tank mates go, I have not kept many other fish with Discus, but definite "No-Nos" are sucking catfish, flying foxes, angelfish and medium to large cichlids. I don't recommend putting any other fish with very small discus, except maybe a catfish or two.
Lastly to make the tank a home, the basic requirements in my opinion are a temperature of 29บ - 30บC for all types of Discus, except maybe Heckel's Discus (Symphosidon discus). Mine seem to grow better at around 32บC. The water should be slightly acid and soft. However, it is more important in my opinion, that it is clean. A pH of around 6-7 is ideal for a display tank and it should not be allowed to go below pH 5.5, where the water becomes unstable. For breeding it may necessary for some pairs to drop the pH a little lower. However, I have successfully bred Discus at pH as high as 7.