"Essay" on Drop Eye (from a physician/biologist)

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Bro
if your familiar with silver arowana
you should know they have a special ability to see up and down at the same time!
in the amazon they only hunt bugs when the water level is high and trees with bugs are easy prey!
when the water level is low they hunt fish which i doubt are only on the surface.
p.s why do BLACK arowana have a lesser chance on DE
thus meaning it may be genetic or the way silvers build up fat!
 
Great discussion, guys! Exactly the type of feedback I was hoping for.

Obviously no one really knows what is causing drop eye yet. I don't propose the ultimate answer, I just wanted to throw some ideas out there and poke a few holes in others.

I think I was misunderstood at the end of my post. I wasn't insinuating that asians are absolutely immune to the disease. It just seems to me that silvers are MUCH more prone to it. Of course, I'm American and have no first hand knowledge of this, just stories (a terrible way to make a conclusion, I know, but it's all I've got for now.)

And very good point about black arowanas not being as drop eye prone. I have no answer for you on that. That does put quite a hole in my theory.

What I was really hoping for is someone who has done an experiment of some sorts. Maybe grow up two silvers over time varying only one possible aspect of husbandry (diet, environment, etc.). Since this is very unlikely to happen, perhaps we can simply combine isolated experiences using this forum to try and figure this out.

For example: Has anyone raised a silver isolated in a dark-bottomed pond from a fry and it developed drop eye? Has anyone raised one on nothing but floating food sticks? (I have, and mine still developed drop eye). Has anyone had their fish analyzed after its death by a professional to see if anything is actually behind the fishes eyes (this is what I'd be REALLY interested in finding out about)? Has anyone noticed drop eye developing within a week of trauma?

I realize isolated answers to these questions may not help alone. But combined together on this forum we may be able to put this puzzle together a little better. Who knows?
 
WOW! I'm impressed. How on earth did you sedate and perform minor surgery on your fish?! Seriously. What did you use for sedation? I'm intrigued.
 
Gshock;3608690; said:
Agree with bderick on this. also, why would looking down cause it to be fixed in that position? Im still more supportive of the trauma theory. Ill try digging up a thread from a while ago. After a jump, both eyes popped out, but one nearly ripped out.

edit: found it
http://www.monsterfishkeepers.com/forums/showthread.php?t=216747&highlight=eye+ripped
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I checked out those pics. Jeez. Poor fish! But I wouldn't call that "drop eye." That looks more like true trauma related INJURY.

Right...?

That's not what you guys all consider drop eye, is it? If it is, I'm completely wrong in my perception of "drop eye" and I'm with you on trauma being the culprit.
 
My silver Arowana is developing DE on one of its eye. I bought it fairly young/small, it grew really fast. However, one night I heard this loud smack from the tank--sounded like he jumped and hit the top egg-crate covering I have. The very next morning, one of its eye looked pretty funny to me. One more day came by and it started to look like DE. So currently one eye is somewhat looking down, the other is perfectly normal. Hopefully that will help with this 'investigation'.
 
Scylla;3610333; said:
I checked out those pics. Jeez. Poor fish! But I wouldn't call that "drop eye." That looks more like true trauma related INJURY.

Right...?

That's not what you guys all consider drop eye, is it? If it is, I'm completely wrong in my perception of "drop eye" and I'm with you on trauma being the culprit.
Click to expand...

That's a DE. I have jars, asian and black and they sometimes hit the glass wall or the cover hard still they don't get DE. Trauma is NOT likely the culprit.

I have cut open some dead silver aro's DE before and it contain a lot of air and some kind of yellowish fluid. I'm no Biologist and I'm lacking in equipment, but if some is able to look at that tissue sample or that yellowish fluid or any of it's DE part under the microscope it would be nice. Aro farms in Asian are dark and it sometimes hard to see the fish in the pond but some of them still got DE. I also have a silver aro back in 2002 that have been feeding on Hikari floating stick and still got a DE.

No one can certainly for sure what's the culprit unless someone look it by a biologist.
 
Hopefully this will stay as a good civilized discussion, the last few on this subject became quite heated. It has been a few months so maybe some new things will arise.

I myself believe that head trauma has alot to do with DE. I realize that black aros also bash their heads but seldom get DE, we must also realize that they are a different fish and the head trauma does not affect them in the same way.

I myself have one silver that developed DE in each eye on two separate incidences. Both times severe trauma was sustained and the DE appeared withing the next few hours. There are many others here on MFK that will testify as to the same thing happening with there own silver aro. There is even one jardini owner who claims this.

Another contributing factor that I would believe is the lack of using their eyes. What I mean by this is, after being in the tank the aro will quickly learn it's surroundings and since it is on a feeding schedule it really has no need to look for food or even were it is going. With this the eyes become lazy from under use.
 
Bderick67;3610469; said:
Hopefully this will stay as a good civilized discussion, the last few on this subject became quite heated. It has been a few months so maybe some new things will arise.

I myself believe that head trauma has alot to do with DE. I realize that black aros also bash their heads but seldom get DE, we must also realize that they are a different fish and the head trauma does not affect them in the same way.

I myself have one silver that developed DE in each eye on two separate incidences. Both times severe trauma was sustained and the DE appeared withing the next few hours. There are many others here on MFK that will testify as to the same thing happening with there own silver aro. There is even one jardini owner who claims this.

Another contributing factor that I would believe is the lack of using their eyes. What I mean by this is, after being in the tank the aro will quickly learn it's surroundings and since it is on a feeding schedule it really has no need to look for food or even were it is going. With this the eyes become lazy from under use.
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If trauma is the cause of DE, the what would be the reason od DE in Silver and Asian aros that are keep in ponds? They surely won't get a trauma when it hit hard on the soil as it's not as hard as the glass. Their is not much difference of skull structure of silver and black aros so the impact would still be the same and why black aros seldom have DE? Also I already said this before, but most aros that keep bashing it's head have bump/lump or damage barbels, and mine have no signs of those injury but still have a DE.
 
i have to disagree with the environment theory, sorry. i have kept my silver aro in "blackwater" with lots of tanin to the point where visibility is almost zero when my aro swims in the back part of the tank, but still it got a DE.
 
Thanks again for all the input, everyone. As mentioned, this was simply intended to be an investigation. I most certainly do not want this to deteriorate into a screaming match. Everyone is making excellent points so far. The comment that made me raise an eyebrow the most was the observation that if drop eye is trauma related, how do pond raised aros get drop eye? Again, I have no answer for that one.

I would like to offer my services as a biologist, though. In the unfortunate event of the demise of one of our precious (that also has drop eye), I am willing to study it. I make no promises, but I would really like to get to the bottom of this.

I mean this with all humility, but I feel I may be a rather unique resource since I not only have access to a microscope, but a full pathology lab able to properly stain, fix, and analyze tissue samples. I also work for the Audubon Aquarium in New Orleans and have access to a number of other biologists that may be able to help us out in our investigation.
 
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