eye size

the subject of eye size seems to come up an awful lot when people critique discus....obviously eyes that are in proportion to the body are what's sought after....but what about wild discus?? it seems like they often have larger eyes... any opinions/theories???

[Dennis_Hardenburge]

David
Yes wild fish seem to have larger eyes than domestics, and it also seems wild females have larger eyes than wild males.
Dennis

[Ryan]

Dennis,

Interesting observation about males vs. females. Do you think that wild males, on average, are larger than females in body size? Or is eye size the only thing you've noticed?

I have also seen this in many of the pictures of wild discus. Particularly on many of the RSG's that people post. They seem to have more oval shaped bodies with larger eyes.

The real question is, given the right conditions from a very early age, would wilds grow to have very small eyes in proportion to their bodies, or is it just in the genetics? Do you think the years of selective breeding of tank-raised fish may have influenced the eye size, resulting in domestic fish with smaller eyes?

Ryan

[redlines]

The real question is, given the right conditions from a very early age, would wilds grow to have very small eyes in proportion to their bodies, or is it just in the genetics? Do you think the years of selective breeding of tank-raised fish may have influenced the eye size, resulting in domestic fish with smaller eyes?

Ryan


Ryan,

There is no doubt that selective breeding influence a great amount of factors in the development of tank raised fish.

But, you could do an easy experiment which would answer your question. Take two batches of fry & separate them at birth.

One group you feed a great diet rich in protein like California Black worms & feed them as much as they can handle.

The other group feed poorly.

Take note of the fish growth & the eye sizes and I believe you will see that the fish that receive the better care and diet will have the smallest eyes and the biggest bodies.

It is interesting to note:

While a fish develops and does not receive the best of care the body & growth becomes stunted while the eyes continue to grow out.

We usually state that the fish has large eyes. When in reality they are only large in proportion to their body that never fully developed. Think about it. With humans it is very similar. While genetics play an obvious role there still is some truth in the statement: YOU ARE WHAT YOU EAT.


Wild or domestic I believe that it is the care and attention that we give our Discus that gives them an edge in development over what they would normally receive in the wild.

Andy

[Ryan]

That's kind of what I was getting at. In the wild there is no one feeding those discus blackworms or beefheart 5 or 6 times a day. They're having to forage and dig and search. So though they may not be fat and happy, they survived.

I guess that is what's amazing to me about these importers who are bringing in these little 2" wilds. These fish were born in the rain forest just a few months ago and have had to survive on their own. Imagine how many of them had to die or be eaten in order for just a few of them to make it.

Ryan

[redlines]

Yep yep probably why Discus spawns are in the 200 - 300 range. Just so 10 or so can make it to adulthood??? Who knows?

so, if you've got a wild discus that's btwn 5.5-6 inches and the eyes look sortof large compared to the body, does that mean it had the potential to be one of those often talked about but never photographed 8-9 inch discus??? ;)

[yogi]

All wilds have large eyes, even the ones that are six inches plus. Even if they could reach seven or eight inches they would have large eyes. I will have to look at my confirmed wild males and females tomorrow to check Dennis's theory.

Overall I don't think you see runted and stunted wild discus. These fish would of been culled by nature. Also I have noticed if you try and grow out small wilds. They grow at a slower pace than domestic discus.

I only have one guess as to large eyes in wilds. And for all I know it could be way off. It has to do with the availablity of food in the stage of free swimming to young adults.

[Dennis_Hardenburge]

Jerry
Interesting theory, we really know so little about what happens in nature.
How about larger eyes in wilds because of reduced visibility of the water?
I don't think the larger eyes in females is probably true, but is in the eight wilds I have, of course this could be strain too.
I didn't realize small fish were exported I thought it was only adults or young adults.
Dennis

[Ryan]

Dennis,

I have talked to a few importers and they basically told me that real small discus and angels die off in mass numbers when they arrive. Maybe they are delicate and cannot take all the stress from shipping, or whatever, but this is what I've heard. I know that baby altum angels get brought in and are lost by the hundreds. They say if you want 2 good altums, buy 10 and hope you get 2.

I also talked to Loren of Boxlotfish.com and he said that small heckels (2" or so) normally came in in pretty rough shape. He didn't mention mass die-offs, but I imagine the little ones are probably more touchy when it comes to the different treatments used on them and such.

It is tempting, though, to buy some small wilds, just to say you tried your hand at it. I've seriously thought about it, if I can find them cheap.

Ryan

[Dennis_Hardenburge]

Ryan
It seems a shame to import them when so many are lost.
Also your heckle crosses look great, might not be worms either as some strains will grow to full size before they do much filling out, and I have a feeling those will be large fish.
Thanks for the info
Dennis

[yogi]

A few of the Miami wholesalers have allowed me to visit and buy. When I say small wilds I'm talking about two inches. I have seen both heckels and greens at this size. Some of the greens are already showing a speckling of spots. The smallest browns or blues I've seen are closer to three to four inches. Dennis that is another good theory about large eyes and vision.

Sometimes the fish are in good shape and sometimes rough shape. I'm sure Loren at boxlotfish has seen a lot more than me. I don't keep angels, but I always ask about altums just to see them. They must be real delicate. More than half the time they are sick.

I just want to say from all my visits to the wholesalers one of the neatest finds is. The red hook silver dollars with a heckel stripe. I never bought any, but a large tank of them would look great.

[Francisco_Borrero]

Yogi:
I will try tomorrow to shoot a couple of pictures of my "heckel" silver dollars. I have a 90gal with 8 large silver dollars: 3 Myleus schomburgkii (black barred Myleus) and 5 Methynnis nigripinnis (red hook silver dollars). They are all quite large, as large as they get in captivity. Gorgeus fish, very active and very hungry!!
Cheers, Francisco.

[Francisco_Borrero]

I offered some pix. Either I do it now with a dirty tank, or....don't know when.
Overall view, here mostly red hooks (notice variability in intensity of red in hook and in body blotches). All here males (notice bi-lobed anal fins).

[Francisco_Borrero]

One of the "heckel" dollars.

[Francisco_Borrero]

another group with two black bar ones, and some red hooks. The black bar is very mood-dependant, and with me in front of the tank, they don't show it much. In the morning is usually better.
This picture shows the very different anal fin in female and male red hooks. I only have a female, the largest, with single-lobe anal fin.

[Francisco_Borrero]

the "heckel" dollars are more skidish and don't like to be photographed. Don't believe me ? check this out !

[Francisco_Borrero]

Dear moderators:
I apologize for the intrusion of non-discus pictures in this discus thread. Cheers and thanks, Francisco.

[yogi]

Thanks Francisco, they are nice pictures.