Drop-Eye, current knowledge (2019) ?

[andyroo]

Sage Aquatists,
What is the current thought/consensus(?) on the why & how of drop-eye, particularly in silvers?
It used to be jump/head-bash injury, then fatty deposits from food and most recently I'm reading of excessive lower/benthic level activity & down-looking attention.
The latter suggests to me the use of surface currents, surface plants, of pingpong balls and guppies,
...and no manic bottom stuff like botia, which breaks my heart.

Andrew

 

[islandguy11]

Well I'm no sage aquatist to be sure, but I don't think there's any recent changes in thinking on the subject.
-- Most will agree head injuries could contribute to DE.
-- Many would agree fatty deposits from food could be another possible factor.
-- Regarding excessive lower/benthic level activity and looking down to much, my perception is that abt half think it does and half think it doesn't. I myself am not sure, but decided with my Xbacks not to take a chance, hence they're in solo tanks. That said, in nature, while the water is murkier and they're generally looking up/horizontal, I'm sure Aros look down sometimes for food or danger, so who knows on this point.

There's also some who maintain it's caused by lack of exercise in the eye muscles, so it's good to have other fish, decorations or floating things around them.

But coming back to silvers, which I've never kept, they also seem to just be more genetically prone to DE (arguably more jumping/head bashing doesn't help), at least in aquarium settings -- like many peeps I've only seen 1 or 2 over 20" w/o DE -- if I lived in the US for sure I'd get a jar or black before a silver because of this issue.

 

[andyroo]

Thanks Barrett.

I did eventually find the sticky- I was interested to know if anything had changed since the last time I'd read it- apparently not, which is fine.
So, as expected, I've got maybe 12months (4 through to 11~12") I'll rebuild/parallel the current 100long/show to something wider/lower-profile with a smidgen of circular surface current and set a domed soft mesh lid with hanging plants, maybe over leaf-bottom blackwater with a nice calm African knife & American eel (plus the tiny native guppy), and feed a hyper-varied diet of lean stuff erring hard towards bugs. I'm on it!

Blacks have always been my favourite, but silvers are all that's imported... and that's if I'm lucky. I happen to be lucky right now, so pulling-trigger (maybe prematurely). Thanks again.

 

[islandguy11]

Thanks Barrett.

I did eventually find the sticky- I was interested to know if anything had changed since the last time I'd read it- apparently not, which is fine.
So, as expected, I've got maybe 12months (4 through to 11~12") I'll rebuild/parallel the current 100long/show to something wider/lower-profile with a smidgen of circular surface current and set a domed soft mesh lid with hanging plants, maybe over leaf-bottom blackwater with a nice calm African knife & American eel (plus the tiny native guppy), and feed a hyper-varied diet of lean stuff erring hard towards bugs. I'm on it!

Blacks have always been my favourite, but silvers are all that's imported... and that's if I'm lucky. I happen to be lucky right now, so pulling-trigger (maybe prematurely). Thanks again.

Sounds like you have a good plan (though personally I'm thinking your Aro would grow from 4" to 12" faster than a year, they can grow .5" to 1" a month depending on diet and tank size). Your domed soft mesh lid with plants sounds interesting, would like to see some pix of that when set up.

My 2 X 325 tank lids incorporate a larger plastic mesh. It's not as soft as like screen mesh but it's not stretched super taut and there's some give, which I think/hope softens any head hits compared to glass or polycarbonate. I've also wrapped the glass center cross pieces in yoga mat.

 

[thebiggerthebetter]

I agree with Barrett. Strong overhead light could be added to the good old list.

Josh of Ohio Fish Rescue claims it is mostly the fat in the diet. Him and his father Rich have corrected a lot of silver aros by cutting out the fat deposit above the eye. They have been doing this themselves.

When there is a DE but no fat hanging out, then the cause is different they say and then they don't touch the fish.

I trust them.

 

[Tobiassorensen]

From what ive understand is that silvers are more prone to DE. I have yet to see an black aro with DE even in larger sizes. Ive got some friends who has 70cm+ black aros without DE or any indications on getting or at all. And for asians i have only seen one and thats joey mullens that he corrected.

 

[Leo Messi]

So obviously Silvers are extremely prone to DE. Asians a little here and there and Blacks pretty much zero. I have never ever seen a single Black with any kind of DE. Not even close. Silvers, well, I'd say about half of them get DE. Asian... I don't know, I'd say maybe 5%?

What I thought first is that it could be genetics. But, even wild Silvers are extremely prone to DE - so I don't think it's genetics... unless, maybe, who knows, most "WC" Silvers aren't even WC but farm-raised in Brazil etc.
Next thing ppl said is bottom fish like stingrays etc. but I know ppl who don't have that and their Silvers still have severe DE.
Another thing ppl said is too much light etc. but again, I know ppl who don't have that and their Silvers still have severe DE.
So to me, this absolutely has to be the food & activity. I can't think of anything else that makes sense.

Our Arowanas are generally extremely lazy. They barely ever go full speed or "work" for their food. They swim extremely slow from left to right without ever "working" for their food. And they get more than enough, probably most likely too much food. Then again, kinda weird that Blacks don't get a DE even under the same conditions, ain't it? Well, maybe Silvers are just way more prone to DE.

What I know is that a friend of mine has bought an Asian Aro at the size of about 9¨. Just like me. we bought ours from the same farm at the same time. He went crazy, fed his Aro a sh*t load of food (way too much) and boom, his Aro got an extremely ugly DE. Mine is perfect, because I fed it in a moderate manner.

 

[islandguy11]

I agree with Barrett. Strong overhead light could be added to the good old list.

Josh of Ohio Fish Rescue claims it is mostly the fat in the diet. Him and his father Rich have corrected a lot of silver aros by cutting out the fat deposit above the eye. They have been doing this themselves.

When there is a DE but no fat hanging out, then the cause is different they say and then they don't touch the fish.

I trust them.

Good points Viktor -- owner of one of my LFS has a gorgeous Super Red that's approx. 24" long and about as wide as 1.5 Big Macs lol. It's in a big tank with only 2 or 3 other peaceful fish. Unfortunately though it has DE on one side, which I think is due to over feeding it almost exclusively on super worms.

So obviously Silvers are extremely prone to DE. Asians a little here and there and Blacks pretty much zero. I have never ever seen a single Black with any kind of DE. Not even close. Silvers, well, I'd say about half of them get DE. Asian... I don't know, I'd say maybe 5%?

What I thought first is that it could be genetics. But, even wild Silvers are extremely prone to DE - so I don't think it's genetics... unless, maybe, who knows, most "WC" Silvers aren't even WC but farm-raised in Brazil etc.
Next thing ppl said is bottom fish like stingrays etc. but I know ppl who don't have that and their Silvers still have severe DE.
Another thing ppl said is too much light etc. but again, I know ppl who don't have that and their Silvers still have severe DE.
So to me, this absolutely has to be the food & activity. I can't think of anything else that makes sense.

Our Arowanas are generally extremely lazy. They barely ever go full speed or "work" for their food. They swim extremely slow from left to right without ever "working" for their food. And they get more than enough, probably most likely too much food. Then again, kinda weird that Blacks don't get a DE even under the same conditions, ain't it? Well, maybe Silvers are just way more prone to DE.

What I know is that a friend of mine has bought an Asian Aro at the size of about 9¨. Just like me. we bought ours from the same farm at the same time. He went crazy, fed his Aro a sh*t load of food (way too much) and boom, his Aro got an extremely ugly DE. Mine is perfect, because I fed it in a moderate manner.

Interesting Leo, I didn't know if Silvers were also prone to DE in the wild -- tried researching it a bit a few days ago but couldn't find a good answer. But if so, to me that actually indicates they are more genetically prone to DE, as they're getting it regardless of environment. I wonder if anyone's heard of Asian Aros sometimes getting DE in the wild?

Good points too about not enough exercise -- that's one reason why I throw in small pieces of food at a time (and changing location where I throw each time), so my Aros have to swim and strike each piece, which they do pretty exuberantly. It's like a little hunting game to them (in fact they love to swim down to the opposite end of the tank and come flying in from there to snag food, which they do repeatedly during every feeding until they start getting fuller, then I stop soon after). I think if I just threw all their food into the tank 1 or 2 portions, they would for sure expend less energy during feeding.

Also that's a good comparison with your and friend's experience with Aros from the same farm, that says a lot about diet factor (if all other things were roughly equal). Btw, do you both keep your Aros solo, or with other fish?

 

[andyroo]

Well, for what it's worth, I've had this little 3.5~4" silver for about a week in a 100-long/show with some reasonable long-ways surface current, surface plants (submerged filamentous & duckweed) and 6~7" of freeboard btwn water & top glass. Good-size & relaxed tetras & big angels below, so moderate activity that tends into the upper-third of the tank. Food: he/she gets compost 'roaches & juv. coqui (invasive frog), which he/she hunts from the glass so most of her/his life is looking straight or up. And...

...left eye looks like it's dropping relative to the right already. ...rolled the dice, and so it goes.
If it is new (IE that i didn't notice before- the drop's pretty subtle) and if it is DE, I'd blame overly energetic jumping & smacking the lid. As such I'm now letting the water level drop a little bit more and crossing fingers that it either is not DE or that it correct/heal. Also to add water-lettuce for a softer jump-hunting surface.

Alt., are roaches & frogs particularly fatty?
I have no idea what he/she was fed in the shop or at the importer's QT.

Thanks for input,

Andrew

 

[andyroo]

yes, so, I've put a dozen water-lettuce and seeded with live small 'roaches & coquis. He/she hunts at the surface, scoping each lettuce-head/pad and is keeping self-fed with minimal effort nor disturbance. The front-feeler's come more or less back into position, so touch-wood the eye will also as he/she is still <5" long. Seems to be... though not holding breath.