Tuesday, January 27, 2009
Asian Arowana: Origin and Classification
The Asian Arowana (Scleropages formosus) is a freshwater fish indigenous to Southeast Asia where it inhabits slow moving waters, rivers and streams. Entirely carnivorous it has become an icon of cultural significance for its grace, longevity, incredible colour and stature and has earned the name Dragon Fish referencing the Chinese Dragon.
Currently an endangered species, it is bred under license and close monitoring by the Asian agricultural authorities, and each fish exported outside of Asia is microchipped (see [URL] microchipping [/url] , certified and licensed for transport.
Asian Arowana can be categorised in the following varieties:
- Green Arowana
- Banjar Red (Red Grade 2, Red Grade 1.5, Yellow Tail Green)
- Red Tail Golden Arowana
- Golden Crossback Arowana
- Tong Yang
- Red Grade 1 Arowana (Super Red, Chilli Red)
Each of these varieties has developed completely independently from the others, with each colour originating from a different location in Asia.
- Green Arowana - Indonesia
- Banjar Red - Banjar Nasin
- Red Tail Golden - Sumatra
- Golden Crossback - Malaysia
- Tong Yang - Hybrid between Golden Crossback and Red Grade 1
- Red Grade 1 - Kalimantan (Kapaus River, Sentarum Lake)
Price & Value
Arowana can range in price from a few hundred pounds up to in excess of £250,000. The value of the fish is determined by a number of factors:
- Colour the definition and contrast of the colour increases the value, the more unusual combination and the more striking the colours the greater the value.
- Depth of colour, the more of the body that is coloured the greater the value.
- Dimensions, as always the proportions and size of the fish effect the value.
- Blemishes, sunburn, marks, cuts, bites etc reduce the price of the fish.
- Uniqueness, this takes many forms, if it is through deformity but a completely unique event, the price of the fish can be hugely elevated. Missing tail sections or deformed jaws that occur in a visually appealing way can make the fish very valuable to someone seeking something unusual. If the deformation is irregular it can completely devalue the fish.
- Personality, due to the uniqueness of each fish and how they interact, their personalities and the connection a potential buyer has with the fish can set the value.
- Age, although this does not directly effect the price, many of the above cannot be determined until the fish is approaching 24 months old. This means that although juvenile fish are significantly cheaper, they are a gamble as to the older fish you are purchasing. To guarantee elements the fish must be much older, by which time a higher price will be set. (Even with super red fish, one can not necessarily say if it will be red or orange if purchased below 12 inches).
Care and Ownership
Often there is concern from potential Arowana owners about the investment involved and the risks associated with it. The reality of the situation is that Arowana (with a life expectancy of 20+ years) can be a long term aquatic companion with one of the lowest requirements of care of any tropical species. Well filtered, soft and slightly acidic water at roughly 28C is preferable, however, Arowana are known in captivity to be kept in a wide variety of conditions ranging from a PH4 to PH8 and KH2 to KH20. This will be reflected by the specific fish and its tolerance to the environment but Arowana themselves are very hardy.
Ideal conditions are based around sensitivity to PH and we always recommend owners keep their tanks as close to PH6.4 to PH6.8 as possible.
Arowana are exceedingly tolerant of poor conditions, they are not however tolerant at all to changing conditions. The greatest risk your Arowana will face is a change in environment such as changing the filter, or overfeeding a tank that has too weak a filter. This can cause a spike in ammonia, nitrates or nitrites. It is not the conditions themselves that can be harmful but the change which may result in losing your fish.
A clear example of this is a tank that has been poorly kept for several months. The owner decides to perform a 60% water change with the purest, most perfectly conditioned and correct water. As a result the Arowana becomes unable to swim correctly, starts to rotate in the water and over a week dies. The issue is not the condition of the water but the unexpected change. This same change could be achieved with 10% water changes per week, or even a reduction of the water level and a drip fed increase over several weeks.
Can I keep Arowana with other fish?
Arowana are also highly territorial but establish good relationships with other fish such as Barbs, Parrot Fish and Stingrays. If you desire to keep a number then as a general rule they can only be kept with other Arowana if in groups of 6 or above. As a testament to their individual personalities it is often possible to keep smaller groups of Arowana together if they are individually more sociable.
Always keep watch over your tank and fish to understand the relationship that are forming. Also remember the Arowana’s primary territory is within 16 inches of the surface of the water. If you have fish that regularly swim in this zone they are prime targets for Arowana to pick on. If your tank is not deeper than 16 inches you may find keeping any other fish will be a problem.
I have heard about Droop Eye, is my Arowana at Risk?
Droop Eye is NOT caused by Arowana looking down or feeding off the bottom of the tank!
The scientific cause of Droop Eye is a fatty deposit build up behind the eyes of the fish, this is caused by over exposure to light, high stress levels, poor diet or any combination of these. To avoid droop eye, make sure you keep the fish in good condition, calm and balanced nutrition. Some fish are genetically more susceptible than others.Please see Feeding Information below for specific feeding tips.
Feeding Information
Arowana prefer live food or at the very least floating food. They will not generally eat from the bottom of the tank. To this end keeping your arowana with a suitable bottom feeder may be a good idea to prevent the buildup of detritus in the tank.
Appropriate foods can range from:
Mealworms, crickets, grasshoppers, locus, garden worms, fly, small frogs, small fish, shrimps, beef heart, etc.
The food your arowana will like is very personal to the fish, so try lots of different things and see how they respond.
Some food help to promote colour in your fish. Any food that contains ceratanoids will help develop red and gold colouring in your fish. However, it is recommended to always maintain a varied diet in your fish.
You can also feed live food on material high in ceratanoids, i.e feed carrots or shrimp to mealworms and then the mealworms to the Arowana.
Feeding patterns effect both the size and colour of your Arowana. Overfeeding can make the fish grow faster but can adversely affect both the colour and the long term health of the fish. Since the size, colour and health is very important do not regularly overfeed any Arowana.
For small fish feeding once or twice a day until they lose interest is enough. From six to 12 inches, once per day is enough. Beyond 12 inches you can consider once every two days, or even less.
High protein foods are also often low in nutrients. Food such as Mealworms are similar to crisps for humans. They taste great but do not have high nutritional value, they provide ideal variety but are a poor stable food.
The best food is fresh fish from your local fish market cut into cubes. You may have to starve the fish for up to several weeks in order to train them to eat food that is not live. If you feed live fish then make sure they are properly quarantined and disinfected before feeding them to your Arowana. Other fish are generally more susceptible to parasites which can in turn damage or kill your Arowana.
I have heard about Droop Eye, is caused by food falling to the bottom of the tank?
Droop Eye is NOT caused by Arowana looking down or feeding off the bottom of the tank!
The scientific cause of Droop Eye is a fatty deposit build up behind the eyes of the fish, this is caused by over exposure to light, high stress levels, poor diet or any combination of these. To avoid droop eye, make sure you keep the fish in good condition, calm and balanced nutrition. Some fish are genetically more susceptible than others.
The Breeding Process
Breeding Arowana is an ongoing process there are no specific seasons when the fish breed, however, there are times of year when breeding occurs more regularly.
There is no external way to sex an Arowana, until recently all breeding was done by educated/experienced guess work placing 30 selected fish into a pond and leaving them to their own devices. Characteristically these ponds are approximately 15m by 20m with a mud or silt floor.
Over time, females will lay eggs on the floor of the pond and a male will pass over fertilising them. Following the fertilisation the eggs are collected into the mouth of the male, where they will develop for 4-6 weeks before being released as young fry into the pond.
The pond manager will maintain a constant vigil to identify the presence of "Mouth Brooding" male fish, and when he feels there is enough justification, will call a harvest.
The fish are driven in a large net to the edge of the pond where they can be caught and identified more easily.
Science Facts
Quian Hu is working with the Temasek Life Sciences Laboratory of Singapore to perform the first genetic research on Arowana and their breeding habits. This has huge potential for our understanding of one of the most ancient species of tropical fish and also how we produce them commercially.
Mr Alex Chang is the primary research fellow working on the project and I had the pleasure of discussing his most recent findings with him relating to breeding.
Now with the ability to sex fish using DNA they are for the first time able to track and understand the breeding process that occurs with Arowana. Incredibly Arowana are both monogamous and promiscuous, some fish will partner for life whereas others will form lasting relationships but with four females or four males. Interesting it is also not always the same male who parents the eggs that collects them in their mouth for development. They have found often an unrelated male will collect the eggs and brood with them. There is no genetic reason for this and currently it is thought it may be a preparation for future mating or to impress females.
They are also attempting to explain the reason for Arowana breeding only being able to occur within a few degrees of the equator. It is believed that magnetic variations strongly effect the breeding of Arowana, as outside of this area they have no interest, but the same fish transported directly to the equator will breed rapidly.
This research marks a monumental occasion for Arowana breeding, allowing for specific strains or characteristics to be bred into the fish and also giving us the opportunity to learn some amazing facts about a species we truly know little about.
I am looking forward to further information from Alex as the research progresses:
