Arowana is a carnivorous fish. In wild, its food consist mainly insects, fishes, prawns, worms and small amphibians. Live food is preferred by arowana though they can be trained to accept other food. Variety in food is a MUST to avoid nutritional deficiency. Small arowana (below 15cm> should be fed three times a day, medium arowana (15-35cm) twice a day and large arowana (above 35cm) once a day or alternate day. 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. 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 quarantine for at least a few days before feeding to the arowana. If you have doubt in certain food, the golden rule is "If in Doubt, Don't Use It". There are always other types of food available.
Insect
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 raise crickets as wild caught crickets may be contaminated with insecticide. You may feed the crickets’ vitamin A rice food 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 using it; any insecticide contaminated cockroach would be death by then.
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 then live one.
Fish
Live fish
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 potential risk of disease transmission when this type of food is used. Quarantine is a MUST as it will screen out most (but not all) sick fishes. 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.
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 enhances 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.
Prawn meat 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 recommended 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 are nutritious food. Rinse away impurities before use. Do not feed it when frozen as it may cause intestinal upset. Avoid old age bloodworms as it is hard for baby arowana to digest. Live bloodworms are preferable 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 claim 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 mean older shell. So choose pale looking mealworm. Drowning the worm proir to feeding is recommended if the fish accept dead worm. Head can be removed to minimize digestive problem.
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 commercial 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.
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. Do not feed death frog to arowana. Frogs are believed to enhance arowana's color.
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 enhances arowana's color. Quarantine is also recommended as they might have eaten insecticide contamination insects, even though the probability is small.
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More post:
Foods you should not feed:
feeders- No nutrition, too many risks, too expensive, depletes B1 vitamins during digestion.
Mamalian Meat- Some people like to feed their aros beefheart and mice. This can be done, but that doesn't mean its good. Fish digestive systems are different that other animals, they do not digest mamalian meats well and repeated feedings of mamalian meats can cuase internal problems.
Live foods- There are too many risks with live foods, parasites, diseases, you name it.
Bugs*- Bugs are a special case, they can be fed, but I added it to this list to say that you should only feed farmed insects. Other insects can be contaminated with pesticides which can potentially kill your fish. Even if you find a couple cockroaches in your house, its usually not a smart idea to feed them as you do not know where they have been.
*Some people feed these things, so I am not telling you that you can't, but rather recommending that you don't, whether you listen or not is up to you*
Baby Aros
Freeze Dried Plankton- This is like minature krill for small aros. This contains alot of karotene which is good for colour and it also floats so its easier for aros to start eating. Remmeber to break off the pointy parts.
Freeze Dried Bloodworms- Freeze dried bloodworms is very nutritious. It is also usually accepted right off the bat so you can use it to get your new baby aros to start eating. This also floats, thus it is easier for baby aros to eat.
Baby Crickets- Aros can almost never resist crickets. They contain no nutrients by themselves so make sure you feed them carrots before you feed the crickets to your aro. Make sure they are BABY crickets as the regular crickets will have a harder exoskeleton and will be too big for the baby aros.
Hikari Aro Foodsticks (broken into smaller peices)- If your baby aro is eating well, it might be time to introduce one of its staple foods, foodsticks/pellets. As long as you break up the pellet/foodstick, it will be fine for your aro. This isn't just for hikari aro foodsticks, this applies with all pellets/food sticks (ie.Tropical Cichlid arowana sticks) but it is just an example as this is very well known.
Market Shrimp (deshelled, defrosted and cut small)- Market shrimp can also be fed to aros at this size. Make sure you remove the shell and defrost fully, as frozen foods can do harm to aros. Cut it really small, small enough for it to fit in an aro's mouth.
Flake- High quality flake can also be fed to baby aros, but should not be fed as they grow as this is not something that could fill up a bigger aro. (thanks to Bderick67 for the tip)
Medium Aros
*Everything in the "Baby Aros" section can be fed*
Hikari Aro Food sticks- At this size, your aro is able to eat full sticks. This should be a staple food. Do not only feed this though, it is best to have variety. Again, this applies to other pellets as well, not just Hikari. Hikari is just an example, this can be applied to all other pellets.
Market Shrimp- Market shrimp now can be fed in bigger peices, usually whole shrimps can be fed when they are deshelled with the tail removed. I personally feed with shell on as the shell contains most if not all the karotene, thus cutting it up into smaller peices is needed. Either way is fine. (WARNING: Feeding the tail has been known to puncture stomachs of aros, so only do it if you feel safe, I wont take responsibility for it.)
Crickets- There is really no need for this anymore and really doesn't need to be part of an aro's diet, but if your aro is sick or has lost its appetite, this is a great food to get them eating again. Again, feed crickets carrots before feeding them to aros.
Mealworms- Mealworms contain alot of karotenoids, like karotene that will boost colours on an aro. Feeding this can be very beneficial.
Fillets- Some people (me included) like to feed their arowana letfover fillets. This is perfectly fine as long as you know 100% that the fillets are fresh. This should not be a staple though, once in a while is good.
Freeze Dried Krill- This is the bigger version of freeze dried krill. All that orange you see is all beneficial karotene that will benefit your aro's colour. Remember to break off sharp points as it has been sceen that sharp peices can puncture stomachs and kill aros.
Mussels, Oysters, kockles- Mussels, oysters, and kockles are all fine tof feed. Shouldn't really be used as a staple though.
Anchovies- Anchovies are high in salt and is very beneficial to the aro's digestive system. This should not be fed too much as salt is very bad is there is too much, but a little bit will clean out their digestive system. (Thanks to Frank for the idea.)
Bloodworms- There is no longer a need for freeze dried bloodworms so you can feed thawed cubed bloodworms. Not recommended that you feed live bloodworms as they can transmit parasites. Also not really necessary in a staple, but thats up to you.
Nightcrawlers- Not the best things you can feed your aros, but it definitely doesn't do any harm. Nightcrawlers eat through the ground and collect minerals as they eat decaying matter. The minerals can benefit fish alot.
Big Aros
*Everything in the "Medium Aros" section can be fed*
Market Shrimp- Your aro should now be able to eat full shrimp with no problems. If you feel comfortable, you can just thaw them and feed them without deshelling or taking off the tail, but again, it has been known that aros die from sharp peices of shrimp tail.
Frogs- Frogs can be fed even at the average size but MIGHT be too big so I added it in the big size. Make sure the frogs you are feeding are not poisonous.
So to end it off, to give you a general idea of a feeding schedule it is only fair that I post my own personal one.
So here it is:
1. Hikari: aro food sticks, carnivore, massivore, cichlid gold- contains most if not all necessary nutrients for an aro
2. Market prawns- whole with shell for big aros, cut up with shell for smaller aros. Shell on for karotene= better colour.
3. Mealworms- for carotanoids again for better colour.
4. Crickets (very rare)- Only used as a treat if an aro is sick or won't eat. Always fed carrots before feeding to aro.
5. Anchovies- Becuase of their high salt content, it is good for a fish's digestive system. But also becuase its high in both salt and fat, I only feed this once every 2 weeks.
6. Krill- I usually don't have krill but whenever I feed like getting some, i will feed it. Also packed full of karotene which is good for colour.
7. Everything else- Ocaisonally, I will have left over fish fillets, mussels, and sometimes oyster.
Source: http://www.monsterfishkeepers.com/forums/showthread.php?t=218052
