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

[badreverend]

i've always been interested in find the truth about DE. maybe it could be a disease?? maybe something deep inside the eye.

that probably wont be a popular answer- but it could help explain why the very similar, but weaker blacks dont get DE- they die before it sets in- Im not saying I agree, but its possible-

I do know that after about 4 or 5 weeks in my backyard pond, my silvers eye was 100%- it lasted 2 or 3 weeks, and now its dropping again- this time Ill take some pictures and record some dates-

Ive seen a few videos of DE surgery and every time a blob of white fat was removed from behind the eye- but the members who cut into their fish found puss or whatever other yellow grossness in there- maybe there is more than one type of DE, the yellow liquid from trauma and the fat from genes or diet or maybe its different stages of the same problem

aros were jumpers due to flooded forests in south america- does the same extreme flooding happen in asia and australia? I dont know if that means anything either- but the blacks...

Im glad the goldfish thing and reflective bottom theories are resting- years ago arowanas were fed goldfish only, because we thought that they would never take less than live- not even frozen fish was used- and I never saw one case of drop eye back then-
but they were also all wild- so the shallow gene pool is at least part of the problem in my opinion-
forcing the fish to look up from the pond seemed to at least temporarily repair the eye also

I guess Ive been thinking about it more than I thought-

 

[fishdance]

There is another aspect to the Drop Eye theory which no one seems to have mentioned yet. When silver arowana strikes for live food, they do want to hit the target/food (of course) but they do not want to hit anything else especially anything hard. This is common sense as food fish are often near the ground, rocks, branches etc. The next time you feed your arowana, watch carefully and you will see how it lines itself up into the classic `S` shaped strike position. Watch it even more carefully and you will see how it thinks-plans just before manouvering itself into the best angle/strike position and how its lunge stops just short of the bottom or side. Now in a pond, black-water, painted back aquarium this is fairly simple but in all clear aquariums this is much harder than you might realise. The arowana knows from experience the tank sides are hard but clear. The arowana knows from experience the sides are somewhere approximately "there". The arowana does know where the food fish is but has a hard time distinguishing the distance between the food fish and the clear hard glass tank wall. Watch its eyes as the aro rapidly shifts eye focus between food fish, outer room wall or furniture (easy to see), back to food fish, then almost invisible glass wall, food fish etc. The aros eyes REALLY work overtime and rapidly unless your tank walls have algae or painted. The aro is constantly fooled by visible things outside the tank which it knows is wrong. It checks and double checks again and again to decide exactly where the clear glass wall is. There is a lot of extra repetitive strain on the eyes in tanks which does not happen in ponds. Also there is a lot of extra collisions into the clear glass walls (miscalculations) in tanks which does not happen in ponds. Whether this extra trauma increases the incidence of drop eye I am unsure but I am confident the pond fish do not work their eyes nearly as much before striking live food.

I wonder if people who feed dry floating food have as much drop eye?

 

[badreverend]

I wonder if people who feed dry floating food have as much drop eye?

when the silver is in the pond all he gets is pellets- when hes in the aquarium its all meaty foods- coincidence?

 

[fish2o]

i have considered all the opinions here about DE, my siver aro has DE on one eye, I noticed the drop eye just after he jumped and banged on the aquarium cover when he got spooked coz im reaching inside my aquarium.

 

[gt1009]

The one problem I have with the OP's idea that they get DE from looking down is that he is basically restating Lamarck's theory of evolution (ie-giraffes have long necks because they keep stretching them to reach high leaves), which has long been accepted as disproven in the scientific community. If this was true, then all the offspring of an aro with DE would have DE. I honestly have no idea what causes DE, but I don't believe it to be always looking down. I would think either head trauma or diet is the most likely cause.

 

[Scylla]

Not exactly what I meant (and Lamarck's theory dealt with passing on traits over time, my theory was in one generation).

Thinking about it some more, this is my latest theory: I agree that trauma seems to be the most likely cause of drop eye. But what about this:

We have heard stories that wild aros, pond kept aros, and aros with overhead stimulus (floating red balls and such) seem to be less prone to developing drop eye. Is it because they have less trauma? I seriously doubt that. This is an insane fish we're discussing. What if these situations allow for better HEALING of the eye after trauma?

Example: An aro bashes his face on a wall and causes eye trauma. Left alone in the artificial environment we usually provide, the eye heals in a downward fixed position (because of the reasons I originally posted). In the other environments we mentioned (with overhead stimulus), after eye trauma, the eye heals with upgaze stimulus and heals in a more natural position.

It's like breaking a bone and not casting it correctly: it heals crooked.

Just another thought to throw out there...

 

[xdragonxb0i]

All Aros can get DE, it is just a matter of time. Koji's silvers might not have DE now, but it still can develop.

No one has really ever though about Stress as a factor. My 10''Silver arowana in a 125, begun devoloping DE, when my dad added koi to my tank. it was obvious it was stressed out. it would swim irratically, He would bump into the side of walls, but he i don't think he ever jump through the lid. I use egg crates, so they should break alot easier then glass lids.


Also other things we should consider is living space.

Silvers are by far the most common and the cheapest. So most aquarist will have Silvers living in smaller tanks which can lead to poor water quality.

Jardini are common too, but since they are more aggressive they would have to be kept alone, and that would lead to less bio load.

We dont see too many Blacks or asains with DE, but they are a lot rarer in the trade.
Also since they fetch a higher price. Most blacks have competent owners. in addition, Asians are gonna get the best of everything because their owners can afford it.

Bad water quality and small living conditions would cause stress. Stress may lead to DE.



I wanna support the trauma theory also, When i was moving the same Silver arowana, with slight drop eye. IT jumped out of the bag and flopped on the floor. When i was able to put him in the tank. the DE got a lot worst, like mild DE.


I think the fatty substance that develop behind the eye is equivalent to callus skin for humans. Callus develop because of irritation/pressure. People who use their hands a lot (construction workers), will have a lot of callus on their hands. The callus protect their hands and skin from ripping and bleeding.


I am currently growing a community of silvers (5) and two jars. The Silvers are from the same suppliers, and the jars are from TFD fish. IF they are wild, the would most likely be caught in the same location; but they could be farm bred (i got them in Dec, at 4''). Either way they would be coming from the same gene pool.


Im gonna test the genetic theory. if one of them get DE, the other will too, because they would share the same gene pool. Environment would not be factor because they are living in the same tank. Would factor that we cant test will be the trauma.

if any of the aros get DE, then it could/would destroy the theory of weak/lazy eye muscles. My aros are always aware of their surroundings because they can be attacked by any other aro. so if they do get DE, i dont think this would be a possible factor for causing de.

 

[Gshock]

http://www.monsterfishkeepers.com/forums/showthread.php?t=297873&highlight=socket&page=4
post #38

Lets go over your points comparing to the case mentioned in post #38
To summarize what happened in that case, 2 aros gets DE over a long weekend (3 or 4 days i assume).

Generally, this is one of the most detailed cases you're going to find on this forum. Going by the given information, the following of your theories are already crossed out:
1. Small tank
2. Fat/callus development
3. Genetics
Why these two won't work? Obivous; becuase 3 or 4 days is definitely not enough time to allow for the eyes to drop due to these factors.

Improbable Theories:
1. Bad water
A 3 or 4 day break without feeding is definitely not going to ruin your water. The average water change schedule is even longer than that. Highly improbable that the eyes dropped due to bad water quality.

So whats left? The most probable one is still head trauma. A long weekend without any human interaction, with all lights off. The only possible factor left is that the aro jumped, hard. Theres alot more points on the post itself that I don't really want to type out again. So, yea... Lets try and make this one of the few GOOD, open DE threads...

 

[sbuse]

This is were I think the lazy eyes thing comes in. Because of what I believe the eye muscle are not used enough in aquarium kept arowana so these muscle grow week. Maybe if the muscles week more active and strengthened DE would be less likely to happen or possibly the aro could even recover from slight DE.

Could be that trauma is a trigger and not a cause. I'm sure the cause is likely a combination of several factors.

the thing with the lazy eye though would be... that if it was just the muscles getting week it would be an easy fix with visual stimulation...unless after the muscle weekens and drops the eye a bodily fluid is drawn in to fill the void created...then over some time thickens (for a lack of a better word) and forms the "fat" deposit found behind the eye...then after this happens it would be perminant...

also with the trama it could be a type of swelling that occurs and due to its location the puss can't retract and that would be the yellow fluid...this could be proven or disproven with the atopsy...with testing on the fluid/deposit of aros with trama as the suggested cause and those that have not had trama...

also in the aro pond farms with the aros with de...they handle the aros to retrive the young... so whos to say that handling no matter how soft we think it may be can result in some sort of head trama? it may be mild at first, but the repeat capturing and removal of fry could add up over time...

Not exactly what I meant (and Lamarck's theory dealt with passing on traits over time, my theory was in one generation).

Thinking about it some more, this is my latest theory: I agree that trauma seems to be the most likely cause of drop eye. But what about this:

We have heard stories that wild aros, pond kept aros, and aros with overhead stimulus (floating red balls and such) seem to be less prone to developing drop eye. Is it because they have less trauma? I seriously doubt that. This is an insane fish we're discussing. What if these situations allow for better HEALING of the eye after trauma?

Example: An aro bashes his face on a wall and causes eye trauma. Left alone in the artificial environment we usually provide, the eye heals in a downward fixed position (because of the reasons I originally posted). In the other environments we mentioned (with overhead stimulus), after eye trauma, the eye heals with upgaze stimulus and heals in a more natural position.

It's like breaking a bone and not casting it correctly: it heals crooked.

Just another thought to throw out there...

it is a good thought and it makes sence...also what if due to the location being in/behind the eye witch is a fragle area, the fluid may not be able to retract...

in addition i feel that trama and genetics are the main cause of de...alot of the "wc silvers come from netted sections of the river were they keep a large group of silvers to "farm" the fry though it is still wild fish to start that get domesticated...

 

[Mr.Nooby]

Well hormones and stress is a factor. iam not sure if much people mentioned about this but maybe turning on your light 24/7 makes them get tire and drowzy...no sleep = stress. maybe the water quality is not good= stress...maybe it's an illness that makes them eye go down. i figure this because i use to have a betta hmpk. i let the light turn on 24/7 and trying to breed it. 1-2 fail attempts and his eye got bigger and drowzier. have same simular eye as a DE arrow would have. sexual stress, sleepless stress, not the right kinda vitamen is another big part...like the topic starter said. fish don't usually store fat much. i disect fish before and only place that have fats are on the belly. some people feed their arrow alot and don't end up with drop eye. maybe drop eye is a trait not a fat problem. common carps are super fat as heck but how come they don't have DE?