Asian Arowana (Scleropages Formosus), also affectionately known as Dragon Fish (龙鱼) in Asia, is native to Southeast Asia. Asian Arowanas inhabit blackwater conditions in rivers and wetland, where the water is soft and acidic.
The Arowana is a geomantic and majestic fish and often regarded as a symbol of luck, wealth and prosperity. Arowana owners believe that if it is treated well, it will protect them from misfortunes and bless them with good fortune and good luck.
Sometimes the Arowana will become ill, but by knowing how to identify the disease, the correct treatment can be administered. Below, we look into some of the more common Arowana diseases, their prevention, and most importantly, how to treat them in the unfortunate event they become sick.
Anchor Worms (Lernaea spp.) are crustacean, copepod parasites. It is parasitic at the Copepodid stage (juvenile) and the female at the Cyclopoid stage (adult).
The female adult will bore into the Arowana usually at the skin, fin and gill area after mating and embed herself in the host tissue using its anterior anchor. The adult female measure about 9mm and appears on the host body as worm-like threads. Poor water parameters and tank conditions will often result in secondary infection, resulting in inflammation and subsequent swelling at the area where female adult burrow into the Arowana.
Most hobbyists will often observe a behavioral change in their Arowanas which alerts them to the presence of the Anchor Worm, e.g. Arowana constantly rubbing against surfaces or ‘darting’. The Anchor Worms are often introduced into aquarium through new fishes or ‘live feed’ especially goldfish.
The optimal temperature range for Anchor Worm is 26–28°C.
Quarantine new fishes and reduce feeding of ‘live feed’ to minimize risk of introduction of diseases or parasites. If possible, treat feeder tank with OceanFree® ‘0’ Anchor Worm & Fish Lice.
Dose OceanFree® ‘0’ Anchor Worm & Fish Lice according to the recommended dosage.
Dose OceanFree® ‘0’ Anchor Worm & Fish Lice according to the recommended dosage. It targets the insect’s nervous system which causes them to turn from transparent to opaque white, the dead Anchor Worm will only drop off the Arowana after 2-3 days.
Repeat medication and perform a 30% water change every 3 days. It is recommended to maintain the treatment for at least 2 weeks even when the Arowana has recovered earlier to ensure that the Anchor Worm has been thoroughly eliminated.
Physical removal is not recommended as it is stressful for the fish and it is not easy to completely remove the Anchor Worms.
Increase oxygenation with an Air Pump during the course of medication. After dosing, observed your Arowana for any signs of distress or heavy breathing for the next two hours. Immediate water change is required should the Arowana appear to be in distress (1/2 tank water change, ensure that the fresh water supply has been properly treated and de-chlorinated).
This is common among Arowanas that has a habit of rubbing their barbels against the tank. Long term abrasion may cause the tissues to become injured. Poor water parameters and tank conditions will often result in secondary infection, resulting in inflammation and subsequent swelling.
This can be identified by a small growth on the barbell and often mistaken for fungal growth.
Important, consult your local veterinarian or a professional for the following procedure.
Increase oxygenation with an Air Pump to help the Arowana regain consciousness after being placed back in the tank. Observed your Arowana for any signs of distress or heavy breathing for the next two hours. Immediate water change is required should the Arowana appear to be in distress (1/2 tank water change, ensure that the fresh water supply has been properly treated and de-chlorinated).
Cloudy white film or grey ‘haze’ that forms over the Arowana’s eye(s) causing the affected eye to appear opaque or slightly opaque. Cloudy Eyes in severe cases will even show as fungal growth on the surface of the eyes. Treatment must be carried out as it may lead to secondary infection and cause blindness if not treated early.
Columnaris or severe Fin Rot is caused by the infection of Gram-negative, aerobic, bacterium Flavobacterium columnare usually through the gills, skin damage or oral access. Symptoms include skin lesions, fin erosion and gill necrosis. It is often mistaken for fungal infection.
The bacteria are prevalent in fresh water. When the Arowana is stressed by factors such as poor water quality, high stocking density, unsuitable tank mates or water with low oxygen levels, it will cause the Arowana to be susceptible to the disease. The disease is highly contagious, with a high degree of mortality.
There are a few possible causes of Drop Eye in Arowanas. Here we explore the most common causes:
Dropsy (also known as ‘Pinecone’, ‘Protruding Scales’ or ‘Edema’) is caused by bacterial infection of the kidneys and is more common in juvenile Arowanas. When the Arowana suffers physical injuries, diseases, weakened immunity caused by poor water conditions, or mucosal damage, it is easily infected by pathogens (virus, bacteria or even fungi.
When the kidney function has been damaged, the Arowana is unable to regulate the body’s water balance, resulting in swelling of the Arowana particularly around the abdomen and causing the scales to protrude. This gives the Arowana a spiky, ‘pinecone-like’ appearance.
Treatment Method
It is common for Arowanas to injure themselves when they hit against rocks, driftwood, equipment, tanks, and tank lids or in fights against other Arowanas.
The main cause of this disease is by bacterial infection. Deterioration of water quality or feeding unclean food will cause an Arowana with weakened immunity to be affected.
Parasitic or physical wounds might also cause secondary infection leading to ulceration.
Fish Lice (Argulus spp) is a parasitic crustacean from the Branchiura subclass. Using large ventral suckers to feed, they usually attach themselves to the tail fin, dorsal fin, abdominal area by piercing through the skin and consuming the blood through the blood vessels.
They measure about 3-5 mm and are not easy to spot. Most hobbyists will often observe a behavioral change in their Arowanas which alerts them to the presence of the fish lice, e.g. Arowana constantly rubbing against surfaces or ‘darting’.
The Fish Lice are often introduced into aquarium through new fishes or ‘live feed’.
Notes
Gills are very important as it enables the Arowana to extract dissolved oxygen from water, allowing it to breathe. Hence ‘Turning of Gill Flap’ is dangerous as it exposes the sensitive gills.
In the initial stages, the gill flap movement will appear irregular and the Arowana’s breathing will become laboured. Next, the gill flaps will start to curl up, exposing the gills. Finally sclerosis (hardening) of Gill Flap takes place, usually accompanied by other gill complications. At this time, the Arowana will find it difficult to breathe and will come up to the surface for air. This will often lead to death.
Stage 1. Gill flap movement is irregular (e.g. unable to open and close properly)
Stage 2. Gill flaps curled up, not hardened yet.
Stage 3. Gill flaps curled up and Sclerosis (hardening) of Gill flap.
Important, consult your local veterinarian or a professional for the following procedure.
Notes
When the Arowana is stressed by factors such as poor water quality, high stocking density, unsuitable tank mates or water with low oxygen levels, it will cause the Arowana to be susceptible to the disease.
The gill is quite often the route of infection as it is the first point of contact where fungal spores and parasite spores are taken in from the water into the Arowana, and soon leading to secondary infection in poor water conditions.
Gill Rot caused by the fungi Branchiomyces sanguinis and Branchiomyces demigrans is contagious. Both fungi grow in the gill area of the Arowana resulting in necrosis (death of gill tissue). Once the gills start to rot, the Arowana will suffer from respiratory problems that often lead to death.
In mild cases of Protruding Anus, fast the Arowana for a few days until the swelling has subsided. Do not feed until the inflammation has fully gone to avoid any relapse.
In prolonged cases of Protruding Anus, there is a need to administer treatment according to the Arowana’s condition as follows:
Increase oxygenation with an Air Pump during the course of medication. After dosing, observed your Arowana for any signs of distress or heavy breathing for the next two hours. Immediate water change is required should the Arowana appear to be in distress (1/2 tank water change, ensure that the fresh water supply has been properly treated and dechlorinated).
This is a symptom of bacterial infection with the scales appearing to be corroded or damaged. The most obvious feature is a crescent-shaped chip-off at the scale’s edge, sometimes accompanied by a whitening of the scales. It is mostly concentrated in the 5th, 4th, 6th and 3rd row of scales (starting from the highest probability) on the Arowana.
Swim bladder is an important organ that helps the fish maintains its buoyancy. Arowanas affected by Swim Bladder Disease exhibits certain symptoms which includes the fish floating nose down, tail up, upside down or floating/sinking.
Swim Bladder Disease is usually caused by two main factor:
1. Constipation causing the impingement of the swim bladder.
2. Infection of the swim bladder organ, or both Infection and Constipation.
Increase oxygenation with an Air Pump during the course of medication. After dosing, observed your Arowana for any signs of distress or heavy breathing for the next two hours. Immediate water change is required should the Arowana appear to be in distress (1/2 tank water change, ensure that the fresh water supply has been properly treated and de-chlorinated).
Ichthyophthirius multifiliis or more commonly known as Ich, is a ciliated protozoan that attaches itself to the Arowana’s body, skin or gill. Ich is vulnerable to medication only in the Tomont and Theront stages of its biological cycle.
The entire biological cycle takes approximately 7 days at 25°C (77°F) to 8 weeks at 6°C (43°F), thus increasing the water temperature to 30°C can accelerate their biological cycle, allowing treatments to target in the Tomont and Theront stage.