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Discus


Background

Discus (Symphysodon aequifasciatus) come from the soft, slow moving acidic rivers and backwaters of the Amazon. These cichlids are normally found in large groups within dense undergrowths only leaving the groups to spawn.
Discus feed largely on invertebrates and insects in the wild. Other natural sources such as plants and other small fish make up a varied diet, from what is a very much a carnivorous fish.


Basic Care

Discus are renowned as hard to keep and the “Divas” of the fish world. With a little practice and good water hygiene, most fish keepers, if not everyone can enjoy the benefits of a large display of these beautiful fish.

Andrew Soh, a renowned and respected Discus breeder and exporter of Discus, wrote about the three principles..

1) Water: Parameter and Quality
Water parameter is an important factor in discus keeping and also in general fish keeping. But discus is one of those aquatic animals that are more sensitive to water parameter. Water parameter can affect the discus growth and spawning potential. Also, wrong water parameter can be rather stressful and under such condition, they may succumb easily to infection. Therefore, it is vital that we must try to adjust the parameter nearest to their natural habitat. Water parameter covers things like the pH, total hardness, conductivity, and the natural trace elements and minerals in the water. To these, we can use chemicals or incorporate reverse osmosis system or de-ionizer and manipulate to produce the best condition for our discus. With the present knowledge, it is not a difficult task to create a similar requirement that of the natural habitat in our home environment.
Having said that, not all discus must be kept in strict water parameter very similar to that of their natural habitat. Discus can be divided into two groups : one is the wild discus while the other group is the domesticated discus. As the wild discus were hatched and raised in the wild, it is only logical to presume that they will thrive well in an aquarium of water parameter very similar to their natural habitat. But with domesticated discus, hatched and raised in an aquarium, they are more tolerable and adaptable to new environment, thus they can thrive well in most type of water provided for them, so long as there is no extreme, be it positive or negative, in any one of the factors.
Quality of water is an even more important issue than water parameter though it basically focuses on variable factors like ammonia, nitrite and nitrate levels; other factors like the temperature; and the amount of dissolved oxygen. Pathogen count is also part of water quality. Any undesirable change in one or in combination of these factors can lead to infestation, infection, deformity, retarded growth or mortality.

2) Feed: Type and Regimen
The Chinese saying goes, “Infection comes from ingestion” and is a true statement even in fish culture. Live freshwater aquatic animals like tubifex, mosquito larva and bloodworms carry along with them smaller organisms. When these organisms are introduced into the aquarium setting, most of them become pathogenic to the discus. And because of the confined water volume within an aquarium, discus are under constant attack and once the water quality drops, a condition is created which favours pathogen proliferation leading eventually to infection and mortality. Therefore, type of feed is very important. As much as we love to pamper our little creatures in the water, it is always my conviction not to feed any frozen or live freshwater aquatic animals. Any food source derived not from freshwater and processed food that has gone through cooking are my choices.
Feed regimen is also an important factor in fish culture. Though the number of feedings per day has a direct relationship with growth, the wider the span of feed, the faster will your discus grow. In simple terms, a discus fed 1 gram per feed and fed 3 times a day at 6.00am, 3.00pm and 10pm will growth faster than a discus fed 1gram per feeding and fed 3 times a day at 8.00am, 12.00noon and 5.00pm.

3) Treatment: Diagnosis, Understanding and application
Diagnosis is the first step in fish treatment and after having diagnosed the state of the problem, the next thing we need is the understanding of the relationship between status of the fish and the prospective treatments. In other words, we must have full understanding of the cause of the problem and the condition of the fish; the tolerant level of the fish at that state to different treatments; the properties, strength and weaknesses of the pathogens; understanding the possible interaction among the different drugs and chemicals and their effectiveness on the pathogens and importantly, whether the use will be harmful to us and our family.
Finally, before we proceed to make the treatment, we must decide on the best treatment regimen to follow. It must be a regimen that is the least stressful to the fish; one that ensures the highest chance of recovery in the shortest period with the least concoction or range of drugs and chemicals used; whether the treatment needs to be applied in water as well as in feed; and whether the fish will have side-effects or permanent damages after recovery. These are important considerations during application as it has been well documented that overdosing of certain drugs or chemicals, be it in quantity and/or duration may damage certain organs e.g. the swim bladder, the liver, and the reproductive organ.

Breeding.

Breeding Discus is not the hardship many think. Once you have your three principles, and your Discus happy in their environment, breeding is inevitable.

Discus are egg brooders, producing 200 – 500 eggs in a batch and watching over them for many weeks until the fry are able to fend for themselves.

The process starts at the courting ritual. Many have observed, including myself, the intricate courtship of flicking and bowing as they eye up their potential mate.
Once they have “paired up”, they look for a suitable site to lay their eggs. This normally follows by a day or two of cleaning and warding off any unwelcome guests near the site.
At this stage, through careful observation, you will be able to see the sex organs descend from the opening just in front of the anal fin. Also your Discus will become darker in appearance. Darkening of the Discus is very much dependent on strain and surroundings. My Blue Diamonds, for example, do not really go dark, whereas Blue Snakeskin’s can almost look sick in their appearance. The darkened area is normally to the rear of the fish and can often be noted that stress bars are visible to the rear of the fish.

Many new discus pairs will have trouble getting the spawning process correct for the first few attempts. The whole process can look awkward and unorganized with both fish not being sure what to do. The newly formed pair should be left alone in the community tank until they have become accustomed to mating. Then they should be removed into a prepared breeding tank, normally of 80 litres and containing a simple mature sponge filter and heater.

The process.
Firstly the female will lay a run of eggs up the chosen site, followed quickly by the male, laying milt over the egg run.

The whole process lasts about an hour and is one of the most wonderful experiences in fish keeping I have yet to surpass. Watching your first pair is truly amazing!

Over the next 3 days, the pair will watch over and carefully fan the eggs, keeping oxygen and water flow over the area. This also works to protect the precious eggs from parasites and fungus that can quickly overcome unattended offspring.

On the third day, if you watch closely, you will see small tails popping out of the eggs as they move to the next stage of development: “The wriggler”. Normally the parents will now move them away to a readily cleaned and prepared hatching site.

Wrigglers now start flexing their tails getting ready to leave the spawning site. If you are lucky to get a large brood, this often looks like a sea of tiny tails flowing in the water current.
As the wrigglers grow, they become stronger and start to propel themselves away from the site. The parents are certainly not too keen about this and pick the little fry up in their mouths, give them a good chew and spit them back onto the hatching area.
Eventually the parents will give up and become overwhelmed by the whole ordeal and the fry will, at last, become “free swimming”.


Free swimmers are classed as the fry’s first day when you, as the breeder, can start to observe the fry’s behaviour.

Fry have very little perception of their surroundings at this stage and possibly can only see different shades of light...

This darkening works like a homing beacon to the fry and they will stay close to the parents for the next 2 or 3 weeks. A good point to note is that anything in the tank that is dark can also work as a homing beacon and can confuse the fry, leading to starvation and death. Therefore it is good practice to keep any dark items in your breeding tanks to a minimum.

Since the start of breeding cycle, your fish have been producing a milk-like substance called mucus from their body. This substance is what your fry will rely on in its first weeks. The mucus contains all the vital nutrients your fry need along with the parents natural immune antibodies.

This mucus is an amazing substance, which very few other fish produce for their young. It can be likened to milk produced by our own species and its properties.

After 4 or 5 days free swimming, you can start to supplement the fry’s diet with Baby Brine Shrimp and, after 3 weeks, the fry are more reliant on the BBS than the mucus from the parents. This stage of development where they are receiving less and less antibodies from the parents is a critical stage as the fry create their own immune system. At this point you, as the breeder, need to watch and maintain a spotless environment for your fry. Many breeders know this stage as 4-week syndrome.

Culling deformed fry is something that is necessary. It is not an enjoyable process but a task that needs to be done to make sure your fry stay in top condition and not competing for food with fish that will most probably not survive past 5-6 weeks.

Medication.

Caring for your Discus involves at some point medicating your fish.
It is very easy to shotgun med your tanks with numerous bottles bought from your local fish shop.

One thing that is imperative is that careful planning and following “exactly” the methods described on the bottle is paramount.

An interesting point Andrew Soh wrote about was flys response to drugs:

Resistant Pathogens
I am very sad to say this ‘The world of pathogens is triumphing over the human race’. Pathogens regardless of whether they are protozoan, worms or bacteria are getting more and more resistant to certain chemicals, drugs and certainly a wide range of antibiotics. Who is at fault? It is 100% ours’…the so-call “The most intelligent beings on this planet”. Humans keep making mistake after mistake because many breeders and hobbyists lack the necessary treatment knowledge to handle a discus crisis, thus allowing microorganisms to survive through the treatments, adapt and mutate into more resistant strain and eventually outsmarting us. Below is an example of an investigation by scientists where the insect became resistant by the end of the experiment.

Example: An experiment was done on ‘Insect reaction to constant treatment with chemical’.
The insect used for this experiment: Housefly. The chemical used was: Diptrex, also known as Masoten, Dylox, Trichlorfon or Neguvon.


Day one: A lot of houseflies were put into a clean empty glass container. Diptrex at lethal level was sprayed into the container. All the flies died within seconds.
Day two: A similar amount of flies were put into the same container. The container was later sprayed with the same concentration of Diptrex. All of them died within a minute.
Day three: Same amount of flies were again put in the same container, and half an hour later, was sprayed with the same concentration of diptrex. Some of the flies died while others struggled and finally survived through the treatment.
Day four: The surviving flies that were still in the container were reused for the next experiment. This time, higher dosage of diptrex was used. All the flies did not die.
Day five: The concentration of diptrex was again increased yet not a single fly died.

This experiment gave us a better understanding of insect’s ability to mutate and become resistant. Where is the loophole of the above experiment that has given a chance for the flies to adapt? As you can see from day three, the new flies were put into the container, but there was a grace period before the new treatment of diptrex was given. During that period, those survivable flies must have consumed the low potent or the inactive diptrex from the previous days and found a way to go around it. It is a known fact that too frequent use of diptrex or some other chemical without proper dosage or without 100% clearing off all the remaining inactive residues in the tanks will give rise to the establishment of resistant pathogens.

I have many personal experiences and have experimented with many drugs and chemicals and I regret to affirm the opinion of other professionals that among all the drugs and chemicals, antibiotics are the most misused. Though unable to diagnose and not having a full understanding of the problem are two contributing factors to resistant strains of pathogens, application know-how is the major contributing factor.
Many hobbyists, breeders and even biologists pay attention to the recommended dosage and the treatment regimen. Just browse through all the related books on fish culture and you will sure to agree with me that not a single author, beside myself, emphasizes on the need to have a strict and controlled application system to prevent development of resistant strain of pathogens.

What Andrew said spoke volumes about how we treat and medicate fish. If we do a water change before the treatment has done its job, resistant strains can come back with more strength and ferocity giving us little options on how to treat our fish. Always follow the course through at 100%!!! And never introduce a fish that looks better without proper quarantine procedures on incubation periods of the pathogen you are treating.

Conclusion
With all fish, disease is a common problem. But with careful management of drug administration we can manage and hold back resistant strains that are becoming all too easy to see with the constant need for increased dosage and new meds.
 

 

Article written and provided by : AdamIreland – July 2008