29/08/2016
Droop (Dropped) Eyes
What is the cause of dropped eyes (DE)?
How can it be cured?
Will it relapse?
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.
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.
sours: http://www.arofanatics.com/
