Drop eye, to the extreme

[sbuse]

One of the possible the theoretical ideas that could help to fill the gap would/could be the genetics theory. Since blacks, jars, leis, and Africans are not farmed as heavily if at all in some cases, they would be less likely to get it. Asians are farmed, but in outdoor mud ponds so a combination of the pond structure and the selective breeding for colors plausibly reduce the tendency to get de? Maybe. Arapima are farmed, not quite as heavily but are, could it be that we don't see as many cases of them due to the difference that most are kept in ponds or massive tanks/ponds, at least at a size were they have the power? Maybe. Silvers are farmed more and that could be a reason. As they are not selectively bread like Asians and would be more prone to defects of inbreeding.

One thing I have not seen mentioned is that they are a different species of fish all together. Of the two in the same species silvers are Heavily farmed so they get it. Of the species that include jars, leis and Asians, Asians are the heavily farmed one so they get it. Then for the lower number of Asians with it could be solved by the selective breeding. Of the species that have arapimas and Africans the arapima is farmed and there is a case of one with it.

Now with blacks becoming higher in popularity and short on supply they could be next to be farmed. When that happens future generations could see de in blacks due to this. They would be close enough to silvers for a comparison. Just the amount of time for farming to get the same mix of inbreeding as silvers would need to pass.

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[lloyd378]

Here is an honest question. I am in no way taking sides, nor am I judging anyone.

At what height does everyone keep their arrow tanks? After reading a few of the last posts, I am now contemplating the idea that a tank low or on the ground (like a pond) may help them not develop DE (as they are looking up all of the time instead of down)...... As for instant DE, i feel like mine had it instantly too, just wondering if their muscles behind the eyes just got tired, and gave out, which would have given me instant feel. When my two got it(around 12 inches), we had them on top of a 4 foot stand behind our sofa so that we could enjoy them The tank was 8'x2'x2'ish feet tall. They regularly got spooked when people they didn't recognize would sit down, until the dreaded DE developed, and then they stopped breaching the water, and would just swim to the other end/back of the tank gracefully quick. Is there a poll somewhere where people marked height of tank, they type of arro, and then size of arro, and then DE or not? I'd find that to be an interesting read.

 

[CeD_^]

I am fully aware that i do not convince you. I hardly convince myself, since no one knows precisely, we have been discussing this for years on end what is the cause ofthe far superior incidence of DE in silvers.

All sspecies kept exactly, by everybody, in the same conditions. Yet 90% silvers get it, 5% of all others get.
Cannot be trauma, only, or the maind cause.

It is ( allmost tank raised silvers ) specific. Is it related to something we miss in their food?

Something must be related to tank keeping and food...

I have caught around 20 silves in the amazon and seen dozens of others caught. None had DE.

If food is one of the reason why aros get DE, how come DE happens sometimes on 1 eye ONLY? It should be both eyes. I do not think people get fat to 1 cheek or 1 arm only. haha I guess it is more about head trauma and genetics; too much mass breeding instead of selective breeding. What if the silver aros are bred from parents which already have DE? Chances are greater that the young ones will have DE too; genetics

 

[Miguel]

You all can have a point in the above, last, arguments.

Point is, no one really knows, beyond mere educated speculation.

 

[Bderick67]

One of the possible the theoretical ideas that could help to fill the gap would/could be the genetics theory. Since blacks, jars, leis, and Africans are not farmed as heavily if at all in some cases, they would be less likely to get it. Asians are farmed, but in outdoor mud ponds so a combination of the pond structure and the selective breeding for colors plausibly reduce the tendency to get de? Maybe. Arapima are farmed, not quite as heavily but are, could it be that we don't see as many cases of them due to the difference that most are kept in ponds or massive tanks/ponds, at least at a size were they have the power? Maybe. Silvers are farmed more and that could be a reason. As they are not selectively bread like Asians and would be more prone to defects of inbreeding.

One thing I have not seen mentioned is that they are a different species of fish all together. Of the two in the same species silvers are Heavily farmed so they get it. Of the species that include jars, leis and Asians, Asians are the heavily farmed one so they get it. Then for the lower number of Asians with it could be solved by the selective breeding. Of the species that have arapimas and Africans the arapima is farmed and there is a case of one with it.

Now with blacks becoming higher in popularity and short on supply they could be next to be farmed. When that happens future generations could see de in blacks due to this. They would be close enough to silvers for a comparison. Just the amount of time for farming to get the same mix of inbreeding as silvers would need to pass.

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A couple things discount the genetics for me.You are hard pressed to even find a tank raised silver above 24" without DE. So either wild caught silver get DE once raised in a tank or there are no wild caught silvers in home aquariums. So for the genetics to hold true then there are no wild caught silvers?

Also from what I understand, it takes 3-4 years for silvers to reach sexual maturity. They also only breed once a year with spawns of 50-100. I cant see where breeders would keep and raise silver aro for 4 years to breed them when large specimens are readily available at low cost. So inbreeding seems unlikely especially for multiple generations.

 

[Bderick67]

Here is an honest question. I am in no way taking sides, nor am I judging anyone.

At what height does everyone keep their arrow tanks? After reading a few of the last posts, I am now contemplating the idea that a tank low or on the ground (like a pond) may help them not develop DE (as they are looking up all of the time instead of down)...... As for instant DE, i feel like mine had it instantly too, just wondering if their muscles behind the eyes just got tired, and gave out, which would have given me instant feel. When my two got it(around 12 inches), we had them on top of a 4 foot stand behind our sofa so that we could enjoy them The tank was 8'x2'x2'ish feet tall. They regularly got spooked when people they didn't recognize would sit down, until the dreaded DE developed, and then they stopped breaching the water, and would just swim to the other end/back of the tank gracefully quick. Is there a poll somewhere where people marked height of tank, they type of arro, and then size of arro, and then DE or not? I'd find that to be an interesting read.

The only thing I can say regarding tank height is that IME the silver aros were more often spooked in lower tanks. From what Ive seen the higher the tank the less skitish their nature. The DE with my silver as previously described first incedent tank top at 4.5-5' second incedent tank top around 4'. Current tank is at 5.5' so I basically see eye to eye with my arowana,

 

[Bderick67]

If food is one of the reason why aros get DE, how come DE happens sometimes on 1 eye ONLY? It should be both eyes. I do not think people get fat to 1 cheek or 1 arm only. haha I guess it is more about head trauma and genetics; too much mass breeding instead of selective breeding. What if the silver aros are bred from parents which already have DE? Chances are greater that the young ones will have DE too; genetics

This leads to my thinking that it is more likely a scar type tissue that builds up in the injured area.

 

[JOSCAR05]

What kind???

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It's just a regular silver arowana but he's my very first to own myself. I always thought an arowana was mine just because my dad owned it but to buy one and keep in My tank really makes it feel like its really mine.


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[David R]

why are the largest amount of dried up aro on the floor, silver arowana?

Because silvers are the cheapest, most prolific and most likely to be kept by inexperienced keepers. You're not wrong about them being powerful jumpers and skittish natured, but I think that is only part of the equation.


As for my take on the DE, I believe there absolutely must be something in the DNA of the silver aro that makes it more genetically predisposed to getting drop eye, regardless of the actual causes of it. 99%+ of adult silvers in captivity have it to some degree, maybe 2-3% of asians, <1% of blacks, and completely unheard of in aussies and africans. Across the board they are all housed in fairly similar type set ups, yet DE is basically guaranteed with silvers and almost unheard of with the other species (only a slim chance with asians). Obviously with those statistics it cannot be environmental factors alone, there is something in the make up of the silver arowana that makes it more susceptible to developing DE from those environmental factors that only occasionally cause it in other species.

As for the actual cause? Buggered if I know!!

 

[sbuse]

A couple things discount the genetics for me.You are hard pressed to even find a tank raised silver above 24" without DE. So either wild caught silver get DE once raised in a tank or there are no wild caught silvers in home aquariums. So for the genetics to hold true then there are no wild caught silvers?

Also from what I understand, it takes 3-4 years for silvers to reach sexual maturity. They also only breed once a year with spawns of 50-100. I cant see where breeders would keep and raise silver aro for 4 years to breed them when large specimens are readily available at low cost. So inbreeding seems unlikely especially for multiple generations.

I agree with you on the genetics in terms of inbreeding. I was tossing that out there for the sake of discussion. The part that I go off of for my contribution for genetics is more along with david.

I also think that the de in wild fish would kill it. That could be why they are limited in range by rapids. It also could be that our high flow in the tanks causes them to be more jumpy. Ponds for the most part don't have that flow rate and could contribute to the lack of it. Makes me wonder if someone had a drip system on a tank and just had it filtered by the drip and plants if it would not be as jumpy. I know all my aros that I keep in tanks with sponge filters are less jumpy. At least from my experience. I know once I have my 10x10 running I am going to try an experiment with silvers. It will be planted and high topped. I will raise them until they are big enough to go in pools with mesh tops to prevent smashing into a lid. I hope to be able to reduce or eliminate head trauma from the fish to see if they will still get de or not.

Until then I am going to raise a group of blacks to try for a spawning venture like I have always gone for.


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