Breeding pattern of Arowana (Indo Dragon)

Many hobbyists are keen to know if it is possible to breed Arowanas in the tank. Reasons for this interest vary from individual to individual but the most common driving force we know of is the enterprising spirit.

IN THE WILD

In the wild, the Arowanas prefers to stay in shallow waters (above five feet deep), near riverbanks and in shaded areas. Arowanas prefer these areas not because they are avoiding the elements, but because insects are plentiful in shaded areas and these are their main source of food. Arowanas also spawn in these areas. Parents take care of their young until they are able to feed on their own. This is usually about 50 days after the eggs have been laid and the yolk sacs have disappeared from the underside of the young Arowanas.

IN CAPTIVITY

The conditions of the pond were controlled to be as close to the Arowanas preferred natural environment. Weeds, floating logs and leaves were left in the pond to achieve this effect. Between 30 to 40 Arowanas between the ages of five and seven, half of them male, half of them female were released in the pond. They were left in the pond to allow them to pair themselves off, while the fish farmers observed from afar with binocular.

After sometime (between one and six months): compatible male and female Arowanas couple by themselves. However, this does not mean that with 30 to 40 Arowanas, you will see 15 to 20 pairs. On the contrary, it is sometimes impossible to get even one pair.

The farmers continued to keep a close watch on the pair. About 30 days later, the spawning was successful as the male was seen releasing young Arowanas from his mouth for between three and five minutes before drawing them back into his mouth again. At this stage, a net was dropped into the pond to segregate the couple and their young from the other Arowanas. After the young were free-swimming, they were netted and kept in separate tanks to grown individually, feeding on bloodworms.

Observations have shown that the female Arowana spawns once a year and each successful spawn produces between 30 and 80 young.


The Arowana prefers a 125 gallon tank with a fine gravel bottom, loosely planted, and soft, peaty water with lots of open space above for swimming. The aquarium must be fitted with a tight, heavy cover because the Arowana will jump, particularly when after prey. After breeding, the male Silver Arowana is responsible for carrying the large eggs in his mouth where they mature in 50 to 60 days. When young, these fish are easily harassed by more aggressive species such as Cichlids, Knife fish, large Plecostomus, Catfish, and Ornate Bichirs make good tank mates for the Silver Arowana. A carnivore, the Silver Arowana will eat other smaller fish, water fleas, mosquito larvae, as well as freeze-dried ocean plankton, krill and pellet foods.


Spawning behavior
The fish shows unique courtship behavior. The courting chase takes place from several days to weeks before the pair starts to mate. They will swim in circles with male chasing the female.

About 1-2 weeks before spawning takes place, the fish swims side by side and perform body contact between pair. After the courtship behavior takes place, the female will lay the eggs and then promptly fertilized by the male. After fertilization, the male picks up the eggs and incubates them until the fry can swim and survive independently.

The eggs are large in size about 8-10mm and yolk rich, hatched about one week after fertilization. After hatching, the young larvae continue to live in the male’s mouth for further 7-8 weeks until the yolk sac was totally absorbed. The size of the fry was 45-50mm before they are move out of the males’ buccal cavity.



REMOVING OF EGGS FROM MALE'S MOUTH

In the study, the fertilized eggs were forced extruded from males’ mouth at the 30th day after spawning. The average number of the eggs produced in a single brood was 21 larvae with the maximum number recorded 29.


The eggs are orange-red in color and are large in size with diameter 16-20 mm. Once removed from the parents’ mouth, the half-developed larvae were incubated in glass aquarium tanks, measuring 90x45x45cm. Water temperature is kept around 27-29 degree C using a thermostat heater and dissolved oxygen is maintained at about 5 ppm (mg/l) through continuous aeration of the water. During the first few weeks when the larvae are still having large yolk sac, they tend to remain at the bottom of the tank most of the time. The fry start to swim upward periodically when the yolk sac becomes smaller.

Using the in vitro hatching technique, the survival rate to free swimming stage achieved is 90-100%. The fry will swim freely on the 7th week. Supplementary external live feed (young guppy) was given at the early free-swimming stage to avoid the fry from attacking each other. At the age of the 6th month the fingerlings were reared individually in 75 x 45 x 45cm re-circulating water system tank. At this age the fry measured about 20-25cm length and were ready for market.


Eight pieces of Malaysian Golden Dragon were reared in 5m x 5m concrete tank and water depth about 0.5m. pH of water was maintained between 6.8-7.5 and temperature 27-29oC. A ’spawning room’ were built at one corner of the concrete tank. It is hoped that the condition will create a natural living environment for the fish. Live feed such as crickets, wild guppy, freshwater prawn (Macrobrachium lanchestrii) and gold fish were given daily. Pellet feed was also given as the supplementary food.

MATURITY

The fish attain first maturity from the 4th year onwards and measure between 45-60cm. The fish spawn throughout the year with the peak season occurring between July and December. In nature the male incubates the fertilized eggs in its’ bucca cavity until the fry is free swimming at about 2 months.

Sexual differences are indiscernible in juvenile stage and become apparent after maturity is reached in about 3-4 years. Male posses slimmer and shallower body depth, bigger mouth and more intense color then the females.

The reasons for having wider mouth and deeper lower jaw in males are for eggs incubating purposes. The size of the males’ head is relatively bigger. Male is more aggressive and leading in competition for food.

A brooding male can be recognized by its remarkable brood pouch underside its mouth.



Aro will be mature and ready for spawning when they are 3 to 5 years old. Usually, the spawning will only take place in the pond where it's more natural environment.

Also, pairing them is also another challenge. As it is rather difficult to sexing them, breeders usually put in many Aros into a pond and let them pair themselves.

When pairing has occured, you will see a pair swimming next to each in a circle. By day they swims in slow circles, the male trailing the female; by night they still swim in circles, but at high speed. This courtship will continued for 2-3 months.

Near the end of the courtship, the fish will be getting more excited, they will swim a bit faster all the time and in tighter circles.

At this point they will feed heavily. Then the male will stop following behind the female and the fish swims slowly side by side. In addition, the circle will be even tighter. Sometimes, the male would bite the female's fins, though they may be tattered, but usually the female do not retreat from the male and in fact the bond between the pair will be strengthen, with lots of rubbing and other body contact.

The appetites of the fish at this will drop markedly, though they will still eat little occasionally. Then fish will move in very slow, very tight circles. The female is kept to the tile outside of the circle and would sometimes remain motionless as the male continue to circiling. Occasionally the fish woult both be stationary, rubbing against each other.

Then the fish will stop swimming around and lay quietly just above the bottom, rubbing against each other. Then quite suddenly, they will spawn. With a spasm, the female will release a cluster of eggs, which the male simultaneously fetilised with a near invisible cloud of sperm. Immediately the male began to scoop up the eggs into his mouth. With a very soft touch, he will pick up one by one.

The female may eat a few egg, the male don't but his mouth will be swollen with his brood. The eggs are about 40 to 60 of them with a diameter of 15-18 mm. Orange-red in colour, non-adhesive.

After spawning, both Aro will swim together all the time. When view from the front, the male shows twin oval black markings on his lower jaw. Generally knowns as 'Brooding Marks". The female will swim slightly above the male, with her pectoral fins spread horizontally, like an honour guard.

The eggs will stay inside the male's mouth for more than a month, he may still may not release the fries out but his mouth will be very swollen. During these time, the male may ate a few of the eggs. Soon after the male will release the fries to swim outside for a short period of time. If they fell threatened, they will immediately return to the father's mouth. Also, the fries will always return to their father's mouth at night. The father during this time, his movement is somewhat sluggish and slow, or rest motionless on the bottom or at the surface. He may be more active at night.

About another 2 weeks or so, 60 days after spawning, the fries finally swim free from their father for extended period of time, though they may be close to his mouth but may not return inside. Their yolk sac would be very small by now. Then you may remove the father.

Once the egg sac completely disappear, then you may start feeding live bloodworms or live 'White Clouds'. At this time (60 days after spawning), the fries is about 3 inches long. Then at 120 days, they will be around 5 to 6 inches.

However, some breeding did occured in the aqurium tanks environment, the very first person who successfully did breeding of Arowana is a Japanese, Mr. Hiroshi Azuma in 1989. After nearly 15 years of trying and trying. Subsequently, more and more people succeeded in breeding Aro in aquarium tank environment, after learning from Mr. Hiroshi's experience.

The breeding cycle is generally once per year, but some young female Aro may be up to twice per year.

Hope the above information helps.