Advanced Topics in Keeping Arowanas

1. Tank Maintenance

Why is tank maintenance necessary?

1.1 Clogs can lead to serious deterioration of water quality. The use of Jap Mat, sponges, cotton wool, etc, can lead to clogs. Dirt accumulates on such clogs, and this needs to be cleaned at regular intervals. A good guide is quarterly maintenance. Eg Jan-March, April to June, July to Sept, Oct to Dec. However, the frequency of cleaning depends on the bioload in the tank, amount of waste accumulated (from excess feeding), etc.
It is a good idea to clean the inner parts of the sump at longer intervals, eg quarterly or half yearly. But the filter wool that accumulates dirt, leftovers and clogs easily at the beginning of the sump should be cleaned weekly or during each water change.

1.2 A quest for better water quality
Having kept the tank at the correct ph level, ammonia and nitrite free, the next target for better water quality is to keep the tank free of organic matter, nitrate, raise the dissolved oxygen level. Frequent water changes of 20% each time is highly recommended, preferably on a weekly basis. Addition of material to polish the water, removing organic compounds, hormones,etc is recommended too.
Some materials which the author used is Seachem activated carbon, Seachem Purigen.
Do not use any zeolite at any time. Avoid the use of any material that do not give a description of it's contents. If you don know what it is, you don need it in your tank!

1.3 Background
Many question whether white or black or blue background is better for their arowanas. Blue is considered better for gold arowanas. Based on the author's experience, a black background brings out the true colours of the arowana, and is pleasing to the eyes as the contrast is greater compared to white or blue.

2. Tanning
2.1 To get the colours of the arowanas to be brighter, and vibrant, tanning is recommended to simulate the effects of sunlight. Natural sunlight improves the colour of the arowana whether they are red or gold. Tanning emulates the effects of sunlight, therefore in the home environment where sunlight do not often reach, tanning at the maximum of 8 hours per day is adequate to reproduce the effects of natural sunlight on arowana colours and wellbeing.
2.2 A clear tank also has it's advantages and it is especially recommended for reds to prevent "dropped eye" syndrome. However, as many prefer to have oyama paper as backdrop, other alternatives need to be sought in the event an aro develops DE.

2.3 When do you start tanning an arowana?
Exposing an arowana (gold/red) to sunlight is a good idea at all times, whether the fish is a juvenile, sub adult or an adult.
This is because calcium is better adsorbed in the presence of sunlight. A tan light with adequate UV can be a good substitute for sunlight. Arcadia produces a D3 reptile lamp and an arowana lamp which is very appropriate for hobbyists introducing light into the tank. However, UV is not friendly to human eyes and therefore should be switched off whenever there are humans looking into the tank.
A red undergoes changes in colour through various stages in it's life. Generally, colour begins to grow with the appearance of "cracking in the cheek", and rims beginning to redden. A closer look at the scales would show that red lines could appear at the core, and the colour start "eating in" to fill up the whole scale. Eventually, the scale turns orange, then red. It is also noticed that there is a transition period at the time when the red is at 18 to 19 inches, about two to three years old. During this time, the red could lose colour and become dull looking, only to come back in full bloom with the whole scale turning reddish.
A Gold arowana intensifies in gold as it ages, unlike the red, there is no transition period. It also adapts rapidly to changes in the background and environment just like a chameleon does. While the look may change according to the surrounding, the core colour remains unchanged and is only influenced by the age of the fish. Gold arowanas hybridised with red and RTGs will correspondingly follow the time scale, ie if the red genes are strong, the gold arowana could be showing gold characteristics until the time when the red shows up, thereafter, it turns into a copper looking arowana, neither gold nor red. Hence, the end colour of a hybridsed gold is not confirmed until the full bloom effect which could be 3 years on to 5 years.
The end result of a hybrid is never certain. It adopts the characteristics of both parents, and could bend either way or likely could blend in both. The desired effect is often to have the pearlies of the red, the gold intensity of the gold. The ultimate desired outcome is to add in the genes of the RTG which gives the rims more prominence at the expense of the core colour, a blue base coming from a mix of red and gold genes. It is easier to have such a mix achieve the cross belly effect as well. Tanning helps with the improvement of rim definition in goldies. It helps to speed up the development of red colour in the red at any time.
The downside of tanning is the stress on the arowanas created by the bright light shining in the tank. A 24X7 regime is not recommended, rather, it is advisable to follow the natural order of sunlight and night time, ie a max tanning time of 8 hours is optimal.

3. Community Tanks

It is acknowledged that a single arowana in a tank is easier to groom, has less chances of being mutilated, and therefore is the safest way to bring up an arowana.
Why then, do many start up arowana community tanks?
Knowing the downsides, there are advantages in keeping community tanks. Hobbyists love to own as many arowanas as possible. Space is a constraint, therefore keeping community tanks could fulfill the desire to own many arowanas.

There are a few things to observe when running a community tank of arowanas:

3.1 Aggression
This could take the form of tail nipping at best, and open biting until the scale is penetrated and flesh opened up.
Aggression should be minimised, when a tail is split, the tank needs careful monitoring to ensure the victim continues to eat well, and is adjusting to the aggressive nature of other tankmates. Some quick fix solutions include the addition of a wavemaker to divert attention, increased feeding, removal of an over aggressive arowana. The size of the arowana also counts, usually the smaller arowana is bullied, hence it is advisable to pick community tank pieces with similar sizes, and have adequate numbers of five and above to disperse the aggression.

3.2 Filtration
Doubling or tripling the filtration capacity is highly recommended to ensure better water quality. Frequent water changes of 20% each week is necessary to clear the tank of nitrate and dissolved organics. Addition of activated carbon and Purigen helps improve water quality during the period between water changes. With a community tank, the ph falls a lot faster due to the higher levels of ammonia produced, hence a ph meter is essential to monitor the ph level and to top up the tank with sodium bicarbonate to prevent ph crashes.

3.3 Backup Contingency
In the event of a power failure, a backup is necessary in all community tanks, it is highly recommended to use something like Ranger 90000. Upsizing the battery is a good idea to secure a longer period of airpump supply in the event of a failure in filtration arising from power being cut off

4. Additives

The use of additives to increase arowana's appetite, boost their energy levels is a subject close to the hearts of many hobbyists.

Broadly, there are two types of additives, the vitamin/mineral booster, and the additive used to improve the water quality. The vitamin/mineral booster is a money spinner mainly because the contents are diluted down to a level such as to get the hobbyists to spend more on less. A better solution to deliver vitamins to the arowanas is to get human vitamin liquids from pharmacies and dilute them accordingly. Vitamin/mineral additive is a useful tool to boost the arowanas' immunity against diseases, increase energy levels and maintain good health, as the food supplied to arowanas may not contain adequate vitamins. Arowanas fed on a single item, eg SW is in need of such a vitamin supplementation. Nevertheless, it is advisable not to splurge on vitamin boosters and ignore all the claims touted by booster peddlers, vitamins are all the same, buy the cheapest possible and it works the same too.
The other additives include blackwater, aloe vera, and others. Blackwater is touted to calm an arowana down, there is a belief that there is medicinal value in the leaf extract but it is not known what it is. However, it is known that blackwater leaf extract contains acids that immediately lowers ph level. The same effect could be achieved by other means, eg addition of apple cider vinegar in much smaller quantities with greater effects. Next time you need to lower ph if it is too high for comfort, try using apple cider vinegar. You can buy these at NTUC or Cold Storage and not have to pay an arm and a leg for a leaf extract. Do be cautious when using apple cider vinegar, a drop is equivalent to a couple of puffs from a blackwater bottle, hence it is a lot more economical and possibly more effective. Apple cider vinegar has a lot of health benefits for human beings, and it is a cheap additive.
Aloe vera extract is not necessary unless there are slime coat problems, in which case, the use of epsom salt is preferred.

A third type is a pseudo magic potion, an eg is the popularly used appetiser that many claims has far reaching effects. I call it a magic potion because nothing is known about it's contents. It is better to avoid such magic potions as it could do more harm than good. Every hobbyists' tank have different conditions and no one solution is effective for all.

5. Droop (Dropped) Eyes

What is the cause of dropped eyes (DE)?
How can it be cured?
Will it relapse?

I am summarising the discussions from two posts:

Discussion on Droop Eyes and Fish Diet

Nip&Tuck by DrArk/Eugene

5.1 What is the cause of DE?
Hereditary factor (born with it) is a pre disposing factor, it is observed some Reds and Silvers have a pre existing condition, this has to do with the eye muscles of the arowana in question. In other words, some aros are born with this genetic disposition to have weak eye muscles.
The primary risk factor is traced to environment. Regarding environment, many scenarios can result in arowanas (that has a pre existing condition) move on to develop DE. It may be endogenous, that is the arowana behaving in a certain way like swimming with the dorsal bent at an angle frequently, parking itself in one position so that one eye is active and the other is inactive, etc. Or it can be exogenous, whereby the activities outside the tank can distract the arowana, making it focus one eye on the outside actively. Whether the eye is looking downwards or upwards could also influence DE. Whilst the number of scenarios are too many for us to consider, and even then at the end of the day we are only guessing what happened, the important point is that the arowana's behaviour coupled by the environment within and outside the tank plays a part in making the condition worse. The situation is dynamic and therefore there is no single solution to tackling DE or recommendation that would satisfy all.
Eg activities outside the tank, eg children playing may cause the aro to look down and therefore DE comes. Another aro may be happily swimming up and down the tank and therefore no DE takes place. Yet another aro may not be watching the children, but likes, as a habit to swim at an angle, hence one eye is tilted at any angle most of the time. So if you cover the front of tank, you may solve the DE problem for the first scenario, but not the third. And then conversely, if you add light on top of the tank, the dorsal may straighten, but in this case you solve the third case but not the first. Get the idea?
It is observed that DE does not occur often in arowana community tanks, this could be explained by the fact that the arowanas are actively moving their eyes, having to watch their back all the time.

Come to diet, is it a risk factor?
Many experts downplay the role of diet. The strongest arguments are put forth in the first article above by two doctors. But however, this discussion over fats remains unresolved even when it reaches the end of the article. The arguments are first class, and very well handled. Do read them for better knowledge and information.

5.2 How Can DE be cured?
Firstly, there might not be a cure for DE if there is a genetic disposition for the arowana to develop this condition. If we start on that basis, then any Red can end up with DE if there are risk factors at play. What if an aro has DE, can it be reversed?
Yes.
What can be done by the hobbyist is to alter the environment in which the aro is kept, at one end of the spectrum, the fish can be kept in an FGT or a pond whereby the eye muscles could regain it's original flexibility and become normal rather than drooping at an angle. Six months in such an environment is recommended.
Other ways to reduce the incidence of DE are not really fool proofed, such as putting ping pong balls floating on the surface of the water, adding in tankmates, etc. In the second article, views that a clear tank (with no oyama paper) can help in preventing DE was put forward, but again this is not a fool proof way. Reds kept in clear tanks have also been known to develop DE, one case is a 7 year old red here. Another is a Gan Red which was also kept in a clear tank for 3 years, developing slight DE. So before anyone starts changing their setup, do know that clear tanks do not always work in preventing DE. Focus more on the immediate environment in your own tank, the individual behaviour of the aro, does it bend when it swims, does it remain parked in one position throughout the day, etc. Do be aware that sometimes, the pre exisiting condition is so great that no matter what you do to the environment, the aro will still go on to develop DE.
And if your aro does develop DE, housing the fish in an FGT or transferring it to a pond would be the best solution.

5.3 Will DE relapse?
Yes, if the pre existing condition (genetic) is there for it to develop DE. Changing the environmental factors is one way to minimise the return of DE.