Sunday, November 22, 2009
Friday, November 20, 2009
Breeding Arowana in Concrete Pond
So u want to breed Arowana in your backyard, so hope this can help u
Golden Arowana
The Golden Arowana is the most popular and expensive ornamental fish
native to Malaysia or other Asia country . The best quality of the crossed-back full scale Arowana is the Malaysian Golden Arowana. This variety only occurs in Bukit Merah Lake in the state of Perak, Malaysia. In its natural habitat breeding season
normally occurs from August to October every year. During the season
village folk from around the lake will try to collect the valuable fry at night.
There are two varieties of Arowana commonly inhabit Malaysian water
bodies; a golden variety and a green variety. The green variety is more
common less expensive compared to the golden variety, which sells at a premium. The crossed-back Golden Arowana commonly inhabits the Kerian
River and its tributaries in Perak. In its natural habitat the fish prefer slightly
acidic clean water and unpolluted natural surroundings, especially
shallow and fast flowing rivers with overhanging vegetation on the river bank.
Due the high price of the golden variety the Freshwater Fisheries Research Station (FFRC) started with a few individuals of the wild catch for brood stock. The wild fish were acquired from traditional fish collectors at Bukit Merah Lake in 1990. In 1996 FFRC was fortunate to successfully breed the Malaysian Golden Arowana
in concrete tanks on the first attempt.
Broodstock maintenance
Eight pieces of Malaysian Golden Dragon were reared in a bare-based concrete tank measuring 5 x 5 meters with a water depth about 0.5 meters fenced with plastic netting about 0.75meters high to prevent the fish from jumping out. A spawning room was built in one corner of the concrete tank and some pieces of bogwood were added to help create a natural living environment for the fish. Other decorations such as pebbles and stones were avoided because they may
injure the fish and be swallowed accidentally during feeding. The rearing tank was partially shaded, away from direct sunlight and built in a quiet area. The broodstock were maintained in the rearing tank until the fish reached maturity.
Water quality management
Although the Arowana is a hardy fish the quality of water should be correspond to the pH of water in its natural habitat when reared in concrete tanks. The pH of water in the rearing tank should be maintained between 6.8 - 7.5 and 27 - 29°C. Water was partially changed at about 30 - 35% of total volume and topped up with dechlorinated tap water. The water depth was maintained at about 0.5 - 0.75 meters. Feeding
Broodstock were fed with a variety of food. A balanced diet is very important in helping fish to mature and spawn. The daily diet should be diverse and contain a high protein content. The fish were fed daily with meat-based live food such as wild guppy, freshwater prawn (Macrobrachium lanchestrii), low grade goldfish and chopped fish meat. Pellet feed containing 32% crude protein was also given as supplementary food. Total amount of food provided was approximately 2% of total body weight per day.
Maturity
The fish attain first maturity from around the 4th year onwards at which
point they measure between 45–60cm in total length. The fish spawn throughout the year with the peak season occurring between July and December. In the wild the male incubates the fertilised eggs in its mouth cavity until the fry are free swimming after about 2 months.
Female Arowana have been reported to have a single ovary which contains around 20 - 30 large ova approximately 1.9cm in diameter. Our observations made by dissecting dead mature Arowana reared in earthen pond obtained from private hatchery confirm the single ovary. However, we found around 50 - 60 ova at different stage of maturity. The mature male Arowana also possess single thread-like testis.
Sex differentiation
There are no obvious sexual differences in juvenile fish. These become apparent after maturity is reached at about 3-4 years of age. Determination of sex is based on the body shape and the size of the mouth cavity. Male fish have a slimmer and
shallower body depth, a bigger mouth and more intense colour then the females. The larger mouth and deeper lower jaw in males are for eggs incubating purposes. The size of the males’ head is relatively bigger. Male fish normally seems more aggressive and leading in competing for food.
Spawning behaviour
The Arowana shows very unique behaviour during courtship. Courtship takes place from several weeks to months before the pair starts to mate. The courtship sequences usually are observed at night when the fish tend to swim closer to the water surface. The male chases the female around the perimeter of tank and sometimes the pair circle each other nose-to-tail. About one to two weeks before
spawning takes place, the fish swim side by side with their bodies touching. Eventually the female releases a cluster of orange-red eggs.
The male fertilises the eggs and then scoops them into its mouth where it incubates them until the fry can swim and survive independently. The eggs are about 8 –10 mm in diameter and rich with yolk and hatch about one week
after fertilisation. After hatching, the young larvae continue to live in the male’s mouth for further 7 - 8 weeks until the yolk sac is totally absorbed. The fry leave the mouth and become independent when they reach about 4550mm.
Identifying a brooding male
After mating a brooding male is can be identified by a distended operculum and its swimming behaviour. They don’t seem to feed and look more placid than at other times. A brooding male can also be recognised by a remarkable brood pouch underside its mouth.
Fry harvest
The incubation period (time from fertilisation until the fry released) is normally about 8 weeks. To shorten the period the fertilised eggs can be hand removed from the male’s mouth on the 30th day after spawning. The brooding male should be carefully caught with a fine net and covered with a wet cotton towel to avoid injury and struggling.
The lower jaw of the fish is pulled backward slowly and the body is shaken slightly to release the half developed larvae from the male’s mouth. The larvae are collected in a plastic basin and incubated in an aquarium. The number of the fertilised eggs collected in a single brood is usually about 20 - 35 larvae.
Larvae removed from the male’s mouth
Hatching technique
Once removed from the male’s mouth, the half-developed larvae are incubated in glass aquarium tanks, measuring 90 x 45 x 45 cm. Water temperature is kept around 27 - 29°C using a thermostat heater and dissolved oxygen is
maintained at about 5 ppm (mg/l) through continuous gentle aeration of the water. We generally add about 2 ppm of Acriflavine solution to the water to prevent infection of any injuries suffered by the larvae during handling. Using this in vitro hatching technique, the survival rate to free swimming stage is generally about 90 100%.
During the first few weeks when the larvae still have a 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. On the 8th week the
yolk sac is nearly fully absorbed and the fry start to swim horizontally. At this stage the first live food should be given to the fry. The yolk sac is fully absorbed and the fry become free-swimming at about 8.5cm in length.
Maintenance of fry
During the incubation period the fry do not need to be fed. The fry will swim
freely on the 7th week. Supplementary external live feed such as young guppysor bloodworm can be given at the early free-swimming stage to prevent the fry from attacking each other. The fry are very vigorous feeders and should be provided with ample supply of feed. We recommend a partial water change of about 30% of total tank volume every 2- 3 days to maintain water quality.
Bigger fry about 10 -12cm in length can be fed with freshwater prawn or chopped fish meat to accelerate their growth rate. At 4 months in age we rear fingerlings individually in 75 x 45 x 45cm aquariums to avoid physical defects from fighting with siblings. To enhance the colour and promote the formation of chromatophores we suggest to illuminate with artificial lighting at least 10 -12 hours a day. After 6 -7 months of free-swimming the fry measure about 20 -25cm in length and are suitable for market.
Common problems during
maintenance
We found few problems in maintenance of brood stock. All our fish were healthy but common diseases such as fin rot, cloudy eye and infection of anchor worm (Lernaea) can occur especially after transferring the fish during overall cleaning of tank.
We treat fish suffering from finrot with a saline bath (1% salt) or commercial medication. Some fish suffer cloudy eyes because of poor handling or from being kept for prolonged time in poor quality contaminated water. To overcome this problem partial water changes of about one third of tank volume every two or
three days should be carried out until the fish fully recover. Common salt was
aquaculture Asia transformation in the sector in the coming years. Can it be done?
Breeding technique of Malaysian
golden arowana
added at every water change (1%) until the condition improved. Infection with
anchor worm parasite Lernaea causes the fish to rub its body against the side of tank and lose appetite. The parasites can be removed manually and the infected fish were also treated with Diptrex® at 0.5 ppm (mg/l).
Conclusion
Breeding of Arowana in earthen pond is commonly practised by commercial ornamental fish farms in Malaysia. To start the business the breeding operation needs a large amount of money for the cost of capital such as buying the broodstock and building new infrastructures
So u want to breed Arowana in your backyard, so hope this can help u
Golden Arowana
The Golden Arowana is the most popular and expensive ornamental fish
native to Malaysia or other Asia country . The best quality of the crossed-back full scale Arowana is the Malaysian Golden Arowana. This variety only occurs in Bukit Merah Lake in the state of Perak, Malaysia. In its natural habitat breeding season
normally occurs from August to October every year. During the season
village folk from around the lake will try to collect the valuable fry at night.
There are two varieties of Arowana commonly inhabit Malaysian water
bodies; a golden variety and a green variety. The green variety is more
common less expensive compared to the golden variety, which sells at a premium. The crossed-back Golden Arowana commonly inhabits the Kerian
River and its tributaries in Perak. In its natural habitat the fish prefer slightly
acidic clean water and unpolluted natural surroundings, especially
shallow and fast flowing rivers with overhanging vegetation on the river bank.
Due the high price of the golden variety the Freshwater Fisheries Research Station (FFRC) started with a few individuals of the wild catch for brood stock. The wild fish were acquired from traditional fish collectors at Bukit Merah Lake in 1990. In 1996 FFRC was fortunate to successfully breed the Malaysian Golden Arowana
in concrete tanks on the first attempt.
Broodstock maintenance
Eight pieces of Malaysian Golden Dragon were reared in a bare-based concrete tank measuring 5 x 5 meters with a water depth about 0.5 meters fenced with plastic netting about 0.75meters high to prevent the fish from jumping out. A spawning room was built in one corner of the concrete tank and some pieces of bogwood were added to help create a natural living environment for the fish. Other decorations such as pebbles and stones were avoided because they may
injure the fish and be swallowed accidentally during feeding. The rearing tank was partially shaded, away from direct sunlight and built in a quiet area. The broodstock were maintained in the rearing tank until the fish reached maturity.
Water quality management
Although the Arowana is a hardy fish the quality of water should be correspond to the pH of water in its natural habitat when reared in concrete tanks. The pH of water in the rearing tank should be maintained between 6.8 - 7.5 and 27 - 29°C. Water was partially changed at about 30 - 35% of total volume and topped up with dechlorinated tap water. The water depth was maintained at about 0.5 - 0.75 meters. Feeding
Broodstock were fed with a variety of food. A balanced diet is very important in helping fish to mature and spawn. The daily diet should be diverse and contain a high protein content. The fish were fed daily with meat-based live food such as wild guppy, freshwater prawn (Macrobrachium lanchestrii), low grade goldfish and chopped fish meat. Pellet feed containing 32% crude protein was also given as supplementary food. Total amount of food provided was approximately 2% of total body weight per day.
Maturity
The fish attain first maturity from around the 4th year onwards at which
point they measure between 45–60cm in total length. The fish spawn throughout the year with the peak season occurring between July and December. In the wild the male incubates the fertilised eggs in its mouth cavity until the fry are free swimming after about 2 months.
Female Arowana have been reported to have a single ovary which contains around 20 - 30 large ova approximately 1.9cm in diameter. Our observations made by dissecting dead mature Arowana reared in earthen pond obtained from private hatchery confirm the single ovary. However, we found around 50 - 60 ova at different stage of maturity. The mature male Arowana also possess single thread-like testis.
Sex differentiation
There are no obvious sexual differences in juvenile fish. These become apparent after maturity is reached at about 3-4 years of age. Determination of sex is based on the body shape and the size of the mouth cavity. Male fish have a slimmer and
shallower body depth, a bigger mouth and more intense colour then the females. The larger mouth and deeper lower jaw in males are for eggs incubating purposes. The size of the males’ head is relatively bigger. Male fish normally seems more aggressive and leading in competing for food.
Spawning behaviour
The Arowana shows very unique behaviour during courtship. Courtship takes place from several weeks to months before the pair starts to mate. The courtship sequences usually are observed at night when the fish tend to swim closer to the water surface. The male chases the female around the perimeter of tank and sometimes the pair circle each other nose-to-tail. About one to two weeks before
spawning takes place, the fish swim side by side with their bodies touching. Eventually the female releases a cluster of orange-red eggs.
The male fertilises the eggs and then scoops them into its mouth where it incubates them until the fry can swim and survive independently. The eggs are about 8 –10 mm in diameter and rich with yolk and hatch about one week
after fertilisation. After hatching, the young larvae continue to live in the male’s mouth for further 7 - 8 weeks until the yolk sac is totally absorbed. The fry leave the mouth and become independent when they reach about 4550mm.
Identifying a brooding male
After mating a brooding male is can be identified by a distended operculum and its swimming behaviour. They don’t seem to feed and look more placid than at other times. A brooding male can also be recognised by a remarkable brood pouch underside its mouth.
Fry harvest
The incubation period (time from fertilisation until the fry released) is normally about 8 weeks. To shorten the period the fertilised eggs can be hand removed from the male’s mouth on the 30th day after spawning. The brooding male should be carefully caught with a fine net and covered with a wet cotton towel to avoid injury and struggling.
The lower jaw of the fish is pulled backward slowly and the body is shaken slightly to release the half developed larvae from the male’s mouth. The larvae are collected in a plastic basin and incubated in an aquarium. The number of the fertilised eggs collected in a single brood is usually about 20 - 35 larvae.
Larvae removed from the male’s mouth
Hatching technique
Once removed from the male’s mouth, the half-developed larvae are incubated in glass aquarium tanks, measuring 90 x 45 x 45 cm. Water temperature is kept around 27 - 29°C using a thermostat heater and dissolved oxygen is
maintained at about 5 ppm (mg/l) through continuous gentle aeration of the water. We generally add about 2 ppm of Acriflavine solution to the water to prevent infection of any injuries suffered by the larvae during handling. Using this in vitro hatching technique, the survival rate to free swimming stage is generally about 90 100%.
During the first few weeks when the larvae still have a 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. On the 8th week the
yolk sac is nearly fully absorbed and the fry start to swim horizontally. At this stage the first live food should be given to the fry. The yolk sac is fully absorbed and the fry become free-swimming at about 8.5cm in length.
Maintenance of fry
During the incubation period the fry do not need to be fed. The fry will swim
freely on the 7th week. Supplementary external live feed such as young guppysor bloodworm can be given at the early free-swimming stage to prevent the fry from attacking each other. The fry are very vigorous feeders and should be provided with ample supply of feed. We recommend a partial water change of about 30% of total tank volume every 2- 3 days to maintain water quality.
Bigger fry about 10 -12cm in length can be fed with freshwater prawn or chopped fish meat to accelerate their growth rate. At 4 months in age we rear fingerlings individually in 75 x 45 x 45cm aquariums to avoid physical defects from fighting with siblings. To enhance the colour and promote the formation of chromatophores we suggest to illuminate with artificial lighting at least 10 -12 hours a day. After 6 -7 months of free-swimming the fry measure about 20 -25cm in length and are suitable for market.
Common problems during
maintenance
We found few problems in maintenance of brood stock. All our fish were healthy but common diseases such as fin rot, cloudy eye and infection of anchor worm (Lernaea) can occur especially after transferring the fish during overall cleaning of tank.
We treat fish suffering from finrot with a saline bath (1% salt) or commercial medication. Some fish suffer cloudy eyes because of poor handling or from being kept for prolonged time in poor quality contaminated water. To overcome this problem partial water changes of about one third of tank volume every two or
three days should be carried out until the fish fully recover. Common salt was
aquaculture Asia transformation in the sector in the coming years. Can it be done?
Breeding technique of Malaysian
golden arowana
added at every water change (1%) until the condition improved. Infection with
anchor worm parasite Lernaea causes the fish to rub its body against the side of tank and lose appetite. The parasites can be removed manually and the infected fish were also treated with Diptrex® at 0.5 ppm (mg/l).
Conclusion
Breeding of Arowana in earthen pond is commonly practised by commercial ornamental fish farms in Malaysia. To start the business the breeding operation needs a large amount of money for the cost of capital such as buying the broodstock and building new infrastructures
Monday, November 9, 2009
Lives Feeds For Arowana
Small Arowana (below 6 inches) should be fed three times a day, medium Arowana (6 inches to 14 inches) twice a day and large Arowana (above 14 inches) once a day or alternate day. Variety in food is important to avoid nutritional deficiency. High fat food like feeder fish should only be used sparingly to avoid drop eye problem. If arowana is overfed for a long period of time, it may lost its appetite and starve itself for a periods of a few days. Overfeeding can also shorten the lifespan of Arowana and affect its breeding capability.
In wild, their food consist mainly insects, fishes, prawns, worms and small amphibians. Live food are preferred to Arowana though they can be trained to accept other food. Variety in food is a MUST to avoid nutritional deficiency.
Live food is generally more nutritious then its counterpart. However, the risk of introducing disease into the tank is increased when live food is used. This is especially true when the live food is waterborne (live in water). Live food should be quarantined for at least a few days before feeding to the Arowana.
Types of Food for Arowanas
(Insects)
Crickets:
Crickets are nutritious food for Arowana. The risk of disease transmission is very low. Use the appropriate size crickets for different size Arowanas. Hard shell of crickets should be removed when feed to baby Arowana to avoid intestinal injury. Use only farm bred crickets as wild caught crickets may be contaminated with insecticide. You may feed the crickets' vitamin A, like carrot before feeding it to Arowana. This is a good way to transfer nutrient. Vitamin A enhances color of Arowana (esp. red). Crickets may be frozen to avoid hassle, the percentage of nutrients retained when frozen is uncertain and require further study.
Cockroach:
Similar to cricket. Do not feed dead cockroach to Arowana as it might have been killed by insecticide. It is advisable to keep the cockroach for a couple of days before feeding it. When possible, farm bred cockroaches would be prefered.
Centipedes:
Centipedes are very nutritious food for Arowana. They are commonly used in Asia to enhance and intensify the color of Arowana. Unfortunately the availability of this food is low. Frozen centipedes are more readily available than live ones.
Fishes:
Live Fishes:
Almost any bite size fish that is not poisonous can be Arowana's food. Feeder gold, meadow, baby koi, baby catfish and small chidlid are commonly used. There is higher potential risk of disease transmission when this type of food is used. To transfer nutrient or medication to arowana, you may feed them to feeder fish right before using it. Some fishes, like goldfish are rich in fat and will precipitate drop eye problem. Use them sparingly. Goldfish is also believed to contained enzymes that will lead to nutritional deficiency in Arowana, use it sparingly or avoid using it. Best recommended minimum number of days for quarantine these feeder fishes is at least 5 days.
Fish Meat:
Fresh fish meat can be used. Trim all the fat away and cut them to bite size, wash them before use to avoid contamination of the water. Avoid frozen fish meat as denatured protein may lead to liver and internal organ sickness in long run.
Crustaceans:
Live Prawns/shrimps:
Prawns/shrimps are rich in vitamin A, which enhance Arowana's color. They are very nutritious food. Avoid feeding baby Arowana shrimps as their shells are hard to digest and may cause intestinal injury. Do not leave live prawns/shrimps in Arowana tank as they encourage Arowana to search downward constantly for them and hence may precipitate drop eye. Once again, there is also a potential risk of disease transmission. Quarantine is also required, minimum 5 days.
Prawn Meat:
Or commonly known as Market Prawn. Use only fresh prawns. Avoid frozen prawns unless you are very sure of its freshness as denatured protein may lead to liver and internal problems in long term. Removal of head is recommend as it is hard to digest and also the gill may have high concentration of germs/toxin. Prepare the prawn in bite sizes and wash it before use.
Krill:
Krill is a nutritious food and it is readily available. Use appropriate size krill for different size Arowana. Crush the shell then soak the krill to soften the shell prior to feeding baby Arowana as hard krill may cause intestinal injury.
Worms:
Bloodworms:
Bloodworms are mainly used to feed baby Arowana. They a nutritious food. Rinse away impurities before use. Do not feed it when frozen as it may cause intestinal upset. Live bloodworms are preferrable but commercially available bloodworms are equally good when fresh. Freeze dry bloodworms may also used.
Tubifex Worms:
Tubifex worms are collected in highly contaminated drain and should be avoid unless properly treated. Commercially breed tubifex worms claimed to be cleaner but its source are sometime questionable. Remember the golden rule: "If in Doubt, Don't Use It". This goes to frozen tubifex worms too. Freeze dry tubifex worms are cleaner but possibility of germs survived through very low temperature cannot be ruled out. High heavy metal content in the source is also a worry.
Mealworms:
Mealworms are healthy and nutritious. Avoid feeding them to baby Arowana as their hard shell is difficult to digest and may cause digestive problem or/and intestinal injury. Use worms that have just shed its shell. Darker color means older shell. So choose pale looking mealworm. Drowning the worm prior to feeding is recomended if the fish accept dead worm. Head can be removed to minimise digestive problem. For larger Arowanas, another similar to mealworm, Superworms can be used. They are equally nutritious but cost alot more commerically than the mealworms.
Earthworms:
Earthworms are very healthy and nutritious. Risk of disease transmission is minimal. Squeezing the soil out before feeding is recommended. Or better still, feed the earthworm with nutritious food to clear the soil and transfer the nutrient. This is a highly recommended food by most aquarist.
Pellets/Sticks Food:
There are many commercail pellets/sticks food available. Their nutritious value varies. Choose reputable brand. Pellets/sticks food specially formulated for Arowana is recommended. However, this should not be the only food of Arowana, it's best act as supplementary food. Also, though not scientifically proven, but experience did seem to prove that if feeding on pellets/sticks or even dried shrimps, will caused protruding anus problem to the Arowanas.
Amphibians:
Frogs:
Frogs are very nutritious food for Arowana and are commonly used in Asia. You should be certain that the frogs are not poisonous before feeding them to Arowana. Frogs should be quarantined for a few (3) days before use as they are often collected in padi-field where insecticide is frequently used. Do not feed death frog to Arowana. Try not to feed wild caught frogs cause you just might caught a poisonous species of frogs.
Bull Frogs:
Bull frogs is getting more popular to be used as food for full grown Arowana. It is also equally nutritious. But due to it sear size, usually only the smaller one is selected to feed, and more often, only one is needed for each feeding each day. But it does cost alot more commercially then the usual feeder frogs.
Lizard/Gecko:
Lizards and geckos are also very nutritious food for Arowana and are often loved by the fish. They are usually not commercially available or demand a very high price. Geckos are found in almost every house in tropical region. Catching them is hard work but often rewarded as they enhance Arowana's color. Quarantine is also recommended as they might have eaten insecticide contamination insects, even though the probabilty is small.
In wild, their food consist mainly insects, fishes, prawns, worms and small amphibians. Live food are preferred to Arowana though they can be trained to accept other food. Variety in food is a MUST to avoid nutritional deficiency.
Live food is generally more nutritious then its counterpart. However, the risk of introducing disease into the tank is increased when live food is used. This is especially true when the live food is waterborne (live in water). Live food should be quarantined for at least a few days before feeding to the Arowana.
Types of Food for Arowanas
(Insects)
Crickets:
Crickets are nutritious food for Arowana. The risk of disease transmission is very low. Use the appropriate size crickets for different size Arowanas. Hard shell of crickets should be removed when feed to baby Arowana to avoid intestinal injury. Use only farm bred crickets as wild caught crickets may be contaminated with insecticide. You may feed the crickets' vitamin A, like carrot before feeding it to Arowana. This is a good way to transfer nutrient. Vitamin A enhances color of Arowana (esp. red). Crickets may be frozen to avoid hassle, the percentage of nutrients retained when frozen is uncertain and require further study.
Cockroach:
Similar to cricket. Do not feed dead cockroach to Arowana as it might have been killed by insecticide. It is advisable to keep the cockroach for a couple of days before feeding it. When possible, farm bred cockroaches would be prefered.
Centipedes:
Centipedes are very nutritious food for Arowana. They are commonly used in Asia to enhance and intensify the color of Arowana. Unfortunately the availability of this food is low. Frozen centipedes are more readily available than live ones.
Fishes:
Live Fishes:
Almost any bite size fish that is not poisonous can be Arowana's food. Feeder gold, meadow, baby koi, baby catfish and small chidlid are commonly used. There is higher potential risk of disease transmission when this type of food is used. To transfer nutrient or medication to arowana, you may feed them to feeder fish right before using it. Some fishes, like goldfish are rich in fat and will precipitate drop eye problem. Use them sparingly. Goldfish is also believed to contained enzymes that will lead to nutritional deficiency in Arowana, use it sparingly or avoid using it. Best recommended minimum number of days for quarantine these feeder fishes is at least 5 days.
Fish Meat:
Fresh fish meat can be used. Trim all the fat away and cut them to bite size, wash them before use to avoid contamination of the water. Avoid frozen fish meat as denatured protein may lead to liver and internal organ sickness in long run.
Crustaceans:
Live Prawns/shrimps:
Prawns/shrimps are rich in vitamin A, which enhance Arowana's color. They are very nutritious food. Avoid feeding baby Arowana shrimps as their shells are hard to digest and may cause intestinal injury. Do not leave live prawns/shrimps in Arowana tank as they encourage Arowana to search downward constantly for them and hence may precipitate drop eye. Once again, there is also a potential risk of disease transmission. Quarantine is also required, minimum 5 days.
Prawn Meat:
Or commonly known as Market Prawn. Use only fresh prawns. Avoid frozen prawns unless you are very sure of its freshness as denatured protein may lead to liver and internal problems in long term. Removal of head is recommend as it is hard to digest and also the gill may have high concentration of germs/toxin. Prepare the prawn in bite sizes and wash it before use.
Krill:
Krill is a nutritious food and it is readily available. Use appropriate size krill for different size Arowana. Crush the shell then soak the krill to soften the shell prior to feeding baby Arowana as hard krill may cause intestinal injury.
Worms:
Bloodworms:
Bloodworms are mainly used to feed baby Arowana. They a nutritious food. Rinse away impurities before use. Do not feed it when frozen as it may cause intestinal upset. Live bloodworms are preferrable but commercially available bloodworms are equally good when fresh. Freeze dry bloodworms may also used.
Tubifex Worms:
Tubifex worms are collected in highly contaminated drain and should be avoid unless properly treated. Commercially breed tubifex worms claimed to be cleaner but its source are sometime questionable. Remember the golden rule: "If in Doubt, Don't Use It". This goes to frozen tubifex worms too. Freeze dry tubifex worms are cleaner but possibility of germs survived through very low temperature cannot be ruled out. High heavy metal content in the source is also a worry.
Mealworms:
Mealworms are healthy and nutritious. Avoid feeding them to baby Arowana as their hard shell is difficult to digest and may cause digestive problem or/and intestinal injury. Use worms that have just shed its shell. Darker color means older shell. So choose pale looking mealworm. Drowning the worm prior to feeding is recomended if the fish accept dead worm. Head can be removed to minimise digestive problem. For larger Arowanas, another similar to mealworm, Superworms can be used. They are equally nutritious but cost alot more commerically than the mealworms.
Earthworms:
Earthworms are very healthy and nutritious. Risk of disease transmission is minimal. Squeezing the soil out before feeding is recommended. Or better still, feed the earthworm with nutritious food to clear the soil and transfer the nutrient. This is a highly recommended food by most aquarist.
Pellets/Sticks Food:
There are many commercail pellets/sticks food available. Their nutritious value varies. Choose reputable brand. Pellets/sticks food specially formulated for Arowana is recommended. However, this should not be the only food of Arowana, it's best act as supplementary food. Also, though not scientifically proven, but experience did seem to prove that if feeding on pellets/sticks or even dried shrimps, will caused protruding anus problem to the Arowanas.
Amphibians:
Frogs:
Frogs are very nutritious food for Arowana and are commonly used in Asia. You should be certain that the frogs are not poisonous before feeding them to Arowana. Frogs should be quarantined for a few (3) days before use as they are often collected in padi-field where insecticide is frequently used. Do not feed death frog to Arowana. Try not to feed wild caught frogs cause you just might caught a poisonous species of frogs.
Bull Frogs:
Bull frogs is getting more popular to be used as food for full grown Arowana. It is also equally nutritious. But due to it sear size, usually only the smaller one is selected to feed, and more often, only one is needed for each feeding each day. But it does cost alot more commercially then the usual feeder frogs.
Lizard/Gecko:
Lizards and geckos are also very nutritious food for Arowana and are often loved by the fish. They are usually not commercially available or demand a very high price. Geckos are found in almost every house in tropical region. Catching them is hard work but often rewarded as they enhance Arowana's color. Quarantine is also recommended as they might have eaten insecticide contamination insects, even though the probabilty is small.
Monday, November 2, 2009
過背金龍唯一產地是馬來西亞，原本有二個產區，一是吉隆坡近郊的八丁燕帶（Batang Berjuntai）與位於霹靂州武吉美拉（Bukit Merah），唯八丁燕帶在1979年便因飼養金龍熱潮下，被漁民、釣客、竭澤取魚導致絕跡。而武吉美拉在當地居民護產之下，禁止外地客釣捕，加上政府興建水壩，水域加大，棲息地自然增廣，便使得武吉美拉湖的過背金龍得以倖存，成為唯一僅存的過背金龍產地。
當野生過背金龍採集量日益減少，而市場有需求量，自然有人會想到以人工繁殖的方式來生產供貨，於是便有人利用小型土池來繁殖，但由於野生過背金龍搜購不易，數量不足，達不到產量，因此便在池中摻入紅尾金龍，如此雖有產量，但在品質上與武吉拉過背金龍不可相比，卻都以過背金龍名義銷售，以致在市場上頗受爭議。直到近五年來有心的龍魚繁殖場，驚覺如此非長久之計，因此便逐漸朝向質的改良，篩選種魚來繁殖優質過背金龍，也因此過背金龍有多樣性的變化，例如：武吉美拉藍底過背、靛藍過背、24k金黃金過背、出藍過背、白金過背等頂級銘龍出現市場，更有人將過背金龍與紅龍配種，再經改良而生產出彤豔過背銘魚。
彤豔是優質紅龍與過背金龍經過二代以上雜交的產物，呈現出更多變化的色彩表現
高背紅尾是龍魚繁殖場將過背金龍雜交到紅尾金的產物，可以明顯看出亮鱗只到第五排下半部，背鰭下的小鱗珠幾乎看不到亮點，而且鱗片層次較模糊，沒有立體
過背金龍最大的觀賞樂趣在於牠的霸氣與金屬光澤
过背金龙的基因与表现之关联
由于目前人工繁殖的过背金龙多数不是所谓的纯系直交，因此衍生了所谓的改良种，当然，优质表现的后代称之为「改良」当之无愧，反之就被谑称为「杂交」了；由于过背金龙的鳞底色泽有蓝底跟金底的分野，而其中的金底是属于比较强势的显性基因，所以鱼场在培育改良的过程中如果运用得宜，的确是可以越改越优质表现；比如：原生种的蓝底过背金龙在光泽的表现度上的不足得到强化改善，甚至金底的形态也能培育出真足黄金般24K金的光彩！
只是令人感到美中不足的是鱼与熊掌的不可兼得，也就是蓝底与金底的表现相互制衡；因此，在选购幼鱼阶段的考量重点到底最高指导原则在哪里?这时就有两极化的标准；金底的标准当然是金色的饱和度以及反射光泽的强弱，还有黄色调的浓淡差异；蓝底当然是看鳞底的蓝色饱和度以及反射光泽的强弱，这中间会有一个差异就是同年龄尺寸的个体，鳞框发展的速度会有不同，金底的鳞框发展较为快速，蓝底的鳞框则相对发展慢一些，而爱好者为了要确保选购的过背金龙能够有过背的表现，通常放弃了鳞框发展较低的个体，这样的市场选购指针导致了产地繁殖场的稚鱼养成都在白色容器，其目的是为了让同化作用使得过背金龙在稚鱼阶段就有鳞框高达五排的表现，但这样的做法在某个角度看来是混淆了过背金龙的本质表现；所以，目前一般对于过背金龙的认知选购标准，还是放在鳞框表现的高低，或是有无小鳞珠的表现，因为过背金龙的精髓在于「金」，就如同红龙的「红」是精髓所在一样的道理。
七彩过背金龙的辨识重点
七彩过背金龙，这种高阶的过背金龙由于肯定会过背，小珠鳞的表现也必定符合期望的两排绵密整齐，所以观察辨识的重点不是在于鳞框上达第几排，或者小珠鳞是否两排整齐排列呈现，顶级过背金龙最重要的要件在于「金」度的表现，也就是反射光泽的强度，日本专家所谓的「镜金过背」就是要像图片中的七彩过背金龙一样有着金属板一样光泽反射！这是来自基因的遗传，是无法透过水质、饵料、环境等外在因子所能影响改变的。
七彩過背金龍幼魚（攝影體長18公分）
七彩過背金龍在成魚後的表現，除了最基本的鱗框肯定會過背之外，優異的兩排小珠鱗整齊排列也是特質之一，當然最重要的金屬光澤反射更是其他過背金龍無法相較的，這種金屬光澤的反射到了成魚階段更是表現的淋漓盡致；鱗框的24K金色澤飽和到有著古銅色甚或紅銅色澤，第四、第五排鱗片的金屬藍色是有著重金屬鈷藍的色澤，這是觀賞魚金屬藍色的極致展現！同時在第二、第三排的鱗片表現上是呈現出松石般的輝綠光澤，腹部則有著黃色調表現，而在鰓蓋的部位，濃烈的金桔光芒閃耀動人，而喉部鵝黃色彩的表現甚至超越於 24K黃金過背！伴隨著游動轉體，全身的色彩光澤變幻萬千，令人動容幾近窒息。
七彩過背金龍成魚
當野生過背金龍採集量日益減少，而市場有需求量，自然有人會想到以人工繁殖的方式來生產供貨，於是便有人利用小型土池來繁殖，但由於野生過背金龍搜購不易，數量不足，達不到產量，因此便在池中摻入紅尾金龍，如此雖有產量，但在品質上與武吉拉過背金龍不可相比，卻都以過背金龍名義銷售，以致在市場上頗受爭議。直到近五年來有心的龍魚繁殖場，驚覺如此非長久之計，因此便逐漸朝向質的改良，篩選種魚來繁殖優質過背金龍，也因此過背金龍有多樣性的變化，例如：武吉美拉藍底過背、靛藍過背、24k金黃金過背、出藍過背、白金過背等頂級銘龍出現市場，更有人將過背金龍與紅龍配種，再經改良而生產出彤豔過背銘魚。
彤豔是優質紅龍與過背金龍經過二代以上雜交的產物，呈現出更多變化的色彩表現
高背紅尾是龍魚繁殖場將過背金龍雜交到紅尾金的產物，可以明顯看出亮鱗只到第五排下半部，背鰭下的小鱗珠幾乎看不到亮點，而且鱗片層次較模糊，沒有立體
過背金龍最大的觀賞樂趣在於牠的霸氣與金屬光澤
过背金龙的基因与表现之关联
由于目前人工繁殖的过背金龙多数不是所谓的纯系直交，因此衍生了所谓的改良种，当然，优质表现的后代称之为「改良」当之无愧，反之就被谑称为「杂交」了；由于过背金龙的鳞底色泽有蓝底跟金底的分野，而其中的金底是属于比较强势的显性基因，所以鱼场在培育改良的过程中如果运用得宜，的确是可以越改越优质表现；比如：原生种的蓝底过背金龙在光泽的表现度上的不足得到强化改善，甚至金底的形态也能培育出真足黄金般24K金的光彩！
只是令人感到美中不足的是鱼与熊掌的不可兼得，也就是蓝底与金底的表现相互制衡；因此，在选购幼鱼阶段的考量重点到底最高指导原则在哪里?这时就有两极化的标准；金底的标准当然是金色的饱和度以及反射光泽的强弱，还有黄色调的浓淡差异；蓝底当然是看鳞底的蓝色饱和度以及反射光泽的强弱，这中间会有一个差异就是同年龄尺寸的个体，鳞框发展的速度会有不同，金底的鳞框发展较为快速，蓝底的鳞框则相对发展慢一些，而爱好者为了要确保选购的过背金龙能够有过背的表现，通常放弃了鳞框发展较低的个体，这样的市场选购指针导致了产地繁殖场的稚鱼养成都在白色容器，其目的是为了让同化作用使得过背金龙在稚鱼阶段就有鳞框高达五排的表现，但这样的做法在某个角度看来是混淆了过背金龙的本质表现；所以，目前一般对于过背金龙的认知选购标准，还是放在鳞框表现的高低，或是有无小鳞珠的表现，因为过背金龙的精髓在于「金」，就如同红龙的「红」是精髓所在一样的道理。
七彩过背金龙的辨识重点
七彩过背金龙，这种高阶的过背金龙由于肯定会过背，小珠鳞的表现也必定符合期望的两排绵密整齐，所以观察辨识的重点不是在于鳞框上达第几排，或者小珠鳞是否两排整齐排列呈现，顶级过背金龙最重要的要件在于「金」度的表现，也就是反射光泽的强度，日本专家所谓的「镜金过背」就是要像图片中的七彩过背金龙一样有着金属板一样光泽反射！这是来自基因的遗传，是无法透过水质、饵料、环境等外在因子所能影响改变的。
七彩過背金龍幼魚（攝影體長18公分）
七彩過背金龍在成魚後的表現，除了最基本的鱗框肯定會過背之外，優異的兩排小珠鱗整齊排列也是特質之一，當然最重要的金屬光澤反射更是其他過背金龍無法相較的，這種金屬光澤的反射到了成魚階段更是表現的淋漓盡致；鱗框的24K金色澤飽和到有著古銅色甚或紅銅色澤，第四、第五排鱗片的金屬藍色是有著重金屬鈷藍的色澤，這是觀賞魚金屬藍色的極致展現！同時在第二、第三排的鱗片表現上是呈現出松石般的輝綠光澤，腹部則有著黃色調表現，而在鰓蓋的部位，濃烈的金桔光芒閃耀動人，而喉部鵝黃色彩的表現甚至超越於 24K黃金過背！伴隨著游動轉體，全身的色彩光澤變幻萬千，令人動容幾近窒息。
七彩過背金龍成魚
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