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DISEASES OF AROWANA
When a fish is placed in a artificial environment from its natural habitat, the chances of the fish getting disease is high. The stress due to the changed environment and also other stress factors like different
feeding regime from the natural habitat and bad water quality management will also cause the fish to acquire disease. Therefore, one should be aware that keeping the stress level low is the best way to prevent disease rather than curing the fish after it acquired the disease.
Generally the dragon fish have a great resistance against diseases so long as they are not weakened by
bad treatment, such as spoilt food, polluted and contaminated water, lack of oxygen, sudden change in
water temperature, or other conditions the result of human negligence and ignorance that will cause stress
and injury to the fish. Remember that the fish remains healthy as long as it is allowed to live in an
environment to which it has adjusted.
The List below are some of the more common diseases associated with the dragon fish, their symptoms
and suggested remedies.
1) Tilted (overturned) Gill Covers
* Fouled water as a result of rotting food particles and excretions. The strong presence of NH3, NO2
and NO3 can reduce the content of oxygen in the water.
* Space constraint - When the Dragon Fish is growing, it not only needs nutrition, it also needs a lot of
room to move about. Otherwise, the gill covers may be affected. They may tilt over.
* Change in temperature - The temperature of the water in the aquarium should always be maintained.
The sensitive gills can be affected when it is either too hot or too cold suddenly.
At the initial stage, the movement of the gill covers is not regular and breathing is also faster and abnormal. Next, the gill covers may become concave and the edge may curl upwards, causing the gills to be
exposed in the water.
Finally, at the serious stage, the fish pushes its head up constantly to the surface for air while at the same
time loses its appetite. This means the internal gills have become damaged and probably infected with
bacteria, affecting the function of breathing and this can lead to death eventually.
When it is first discovered that the Dragon Fish is not breathing properly, the water should be changed immediately. Every 2 to 3 days, 20% of the water in the aquarium should be changed. Air pump should
be further activated and air bubble stones could be added so that oxygen level in the aquarium could be increased. Also, change the filter media to coral sand.
When the edge of the gill cover is slightly curled but not yet hardened, other than changing water, and increasing air/oxygen supply, strong water current could be created. There may be 50% chance of a
cure without the need to operate.
When the gill cover is tilted and hardened exposing the gills, the only way left is to trim off the tissues of
the tilted region. Tools needed are scissors, surgical spirit, gloves, plastic bag and a rubber sheet. Also
water-proof fine sand paper to polish clean the gill cover affected by cut tissues. The above tools must
be properly sterilised.
When all equipment have been properly treated, the Dragon Fish should be transferred to a smaller
fish-tank leaving the original tank to be filtered and pumped with air to increase oxygen content. With 1/3
of water in the small tank, anesthesia should be administered within the plastic bag which contains the
sick Dragon Fish. It must be established prior to the operation that the Dragon Fish has completely lost consciousness before it can be removed (take care not to cause dehydration). Then use a clean pair
of scissors to trim the edge of the gill covers.
After cutting, it is necessary to apply antiseptic medications to the trimmed edges. The Dragon Fish
should be promptly put back into its own aquarium to await its regaining of consciousness. More
antiseptic medication may be added to prevent wound from being infected with bacteria.
When it regains consciousness, switch off all lights and allow the Dragon Fish to recuperate. Feeding
can be stopped if it has no appetite. Additional equipment may be fitted to create waves in the aquarium.
The cut portion must grow again before the operation is considered successful.
2) Cloudy Eyes
* Eye-injury as a result of bad handling
* Contaminated water
Initially, one eye may appear cloudy. It then becomes moldy as though a membrane is hanging over it. Eventually, the eyes may swell and are covered with blueish white foreign matter. At this stage, if they
are not treated may result in death or blindness.
At the initial stage 1/3 of water should be changed and coarse salt should be added.
Water temperature should also be increased to 30°C to 33°C. Observe for 2 days. If condition improves,
water should be changed every third day (1/4 of water) and more salt may be added until complete
recovery. At the intermediate stage, medications may be needed to bathe the fish in. Such medications
will have their own instructions to be adhere to on application. When eyes become moldy, recovery may
take 3 to 5 months. If swelling subsides, medication may be reduced or stopped eventually. After
recovery, eyes may appear smaller but that should be normal.
3) Protruding Scales Disease
This often occurs when Dragon Fish is young. The adult Dragon Fish seldom gets affected by this disease.
* Events causing extreme temperature changes within the aquarium.
* Contaminated water.
Initial stage - Scales tilt at every 5th to 8th scale. Blood traces may be seen at the root of scales. If not
arrested at this stage, scales will gradually tilt, redness may appear and the scales will not be able to protect body causing bacteria attacks to the body of the Dragon Fish. The scales may all drop off causing the body
to decay and the fish to die.
Add coarse salt and increase temperature to 32°C to 34°C. Increase oxygen content in the water and
change water (1/4) every 3 to 4 days. Water may be heated prior to change. Add copper sulfate
medications to the water.
4) Rotting Gills Disease
Caused by a type of parasite which cannot be seen by the naked eye. These parasites hide in the gills
sucking and absorbing all the nutrients from the Dragon Fish. The cells of these parasites multiply
speedily at 25°C. This disease is highly contagious.
Polluted water or water which has not been changed for a long period.
The fish is breathing very fast and its color is dull.
Similar to that of the "White Spots" Disease (see section on the "White Spots" disease)
5) Stomach Ailments
This occurs when fish is very young - mainly due to eating stale food or it may have been injured by
the sharp pincer of the prawns causing the internal wall of the stomach to be infected with bacteria,
resulting in a swollen belly.
Initial stage - Swollen stomach with a red swollen anal region. At the advanced stage, the Dragon
Fish may be seen to have lost its balance dipping its head downwards.
At the moment cure is limited, but commercially available fish medications may be given and
water may be changed with temperature increased by 2°C to 3°C.
6) 'Red Spots' Disease
This is often regarded as a terminal disease and it affects mostly young fishes.
Red spots occur on the lower back portion of the body. Early stage - patches of red spots, gradually
swelling occurs, scales are upturned and finally the fish may slowly rot to death.
Try increasing temperature to 36°C plus bathing it with fish medications available commercially.
Most of these parasites come from the live food that are used to feed the Dragon Fish and are
passed to the Dragon Fish during feeding. the parasites that affect the Dragon Fish are mainly the
fish lice and the anchor worm.
Approximately 3 to 5 mm long, can be seen with the naked eye on the external body. It has a
flattened body shell. It has a needle-like structure at the mouth to suck out the body fluid causing the
fish to lose its lusture, at the same time causing the fish to be uncomfortable, scraping the side or
bottom gravel of the aquarium.
Found mainly around the fins or within the body of the fish. The head of the worm is forked and it
sucks the nutrients from the fish directly. The length is about 1 cm. The affected region is often red
and swollen with traces of blood and then decay sets in. An affected fish may appear to be irritable,
scraping and rubbing against the sides of the aquarium and losing its appetite in the process.
The above parasites can be killed by using copper sulfate medications. The fish lice can also be
gotten rid of by keeping the Dragon Fish in a concentrated salt solution. Oxygen content should be
increased in the aquarium during this soaking period.
Note: Once the Dragon Fish has been infected by parasites, the tank must be sterilised.
8) 'White Spot' Disease
This disease is very common among fishes. It originates from a type of ICH bacteria. It can multiply
alarmingly fast, and can flourish at body temperature 25°C from a single cell to 3000 over cells in a
hour. Under high temperature, it can stop multiplying and even die.
ICH bacteria only attack the fish with low resistance. The bacteria suck up the body fluid of the
fish. The affected region looks like white powder.
At initial stage, the disease affects mainly the fins. The fish that has been infected with this disease
tends to scratch itself against the sides or bottom of the aquarium to rid its itch. Its appetite
deteriorates greatly and fin ends starts to rot. Lastly when it attacks the gills, the fish may die.
The illness should be arrested at once as it is highly contagious.
1. 1% salt
2. 0.8 gm of Quinine in every litre of water.
3. Use available commercial preparation from Aquarium shops.
Warm the water by increasing by 2°C to 3°C in temperature and adding air-pumps to increase the
oxygen level in the aquarium.
In the process of treatment, the Dragon Fish should be fed nutritious food so as to build up
its physical resistance. Upon recovery, it is advisable to disinfect the entire aquarium.