# Do All Flounders Lean the Same Way? **URL:** \ **Category:** Factual Questions\ **Created:** [May 12, 2002, 7:50pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668 "2002-05-12T19:50:27Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![delphica](https://avatars.discourse-cdn.com/v4/letter/d/e9a140/32.png) [@delphica](https://boards.straightdope.com/u/delphica)\ **Post date:** [May 12, 2002, 7:50pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/1 "2002-05-12T19:50:27Z")
I saw a nature documentary last night that had flounders, those fish that swim on their sides, and whose eyes have migrated so that they’re both on the same side – that is, the top, if you’re looking at the fish swiming in its environment, or the side, if you’re looking at the fish’s anatomy. The flounder who was the star of this particular documentary had his left side to the bottom, and his right side (with eyes) to the top. Do all flounders hang to the left, so to speak, or do some go to the right? Why? When the flounder ate, his mouth opened sideways, or what looks to be sideways, because he is on his side. (I’m rather freaked out by this so I’m not being very coherant.) In addition to the eyes, are other parts of the flounder’s body (internal or external) shifting around as a result? ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [May 12, 2002, 8:07pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/2 "2002-05-12T20:07:26Z")
I can tell you flounders come in both left and right hand types and I believe it is not just by chance that they develop one way or the other but there is a genetic component attached. Scientific American magazine had an article about this which went deeper into it than anyone would be interested in. ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [May 12, 2002, 8:29pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/3 "2002-05-12T20:29:40Z")
> [@](#): > > \*Originally posted by delphica \* > **Do all flounders hang to the left, so to speak, or do some go to the right? Why?** Both sides, as sailor said. A Google image search shows fish of both types. Why? _For the halibut!!!_ 😃 ---
**Author:** ![berdollos](https://avatars.discourse-cdn.com/v4/letter/b/ed8c4c/32.png) [@berdollos](https://boards.straightdope.com/u/berdollos)\ **Post date:** [May 12, 2002, 8:44pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/4 "2002-05-12T20:44:21Z")
and whjat is the percentage of flounders leaning on the right or lef sides (as their bottom)? Is there any way to change this with little flounders, or to create a flounder that swims normally. I assume the new-borns or fry swim normally. Is this right??? ---
**Author:** ![Ringo](https://avatars.discourse-cdn.com/v4/letter/r/779978/32.png) [@Ringo](https://boards.straightdope.com/u/Ringo)\ **Post date:** [May 12, 2002, 9:00pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/5 "2002-05-12T21:00:16Z")
From a page on [Summer Flounder Development and Adaptation](http://www.gso.uri.edu/faculty/specker/flounderDandA.html): > [@](#): > > Also at this stage their right eye relocates to the left side of their body and they begin to settle into a benthic mode of life. That’s pretty specific about which eye does the migrating. But that’s for summer flounder. [Starry flounder](http://elib.cs.berkeley.edu/kopec/tr9/html/731.html) belong to the family [_pleuronectidae_](http://artedi.fish.washington.edu/FishKey/pleuro.html), or Righteye Flounders, about whom the linked page states: > [@](#): > > Juvenile pleuronectids swim upright near the surface and have bilateral symmetry, but during their development one eye (usually the left) migrates to the other side of the cranium, and the fish takes to lying or swimming near the bottom on its eyeless side. So, they apparently come in both flavors. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 12, 2002, 9:30pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/6 "2002-05-12T21:30:32Z")
In any one species of flatfish (flounders, flukes, halibut, sole, etc.) both eyes of all adults will be on the same side (at least of normal individuals.) Whether this is the right or left side varies between species (and as Ringo’s link indicates, entire families are generally either right or left-sided.) ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [May 13, 2002, 10:45pm UTC](https://boards.straightdope.com/t/do-all-flounders-lean-the-same-way/108668/7 "2002-05-13T22:45:24Z")
I never met any flounders, but I’m pretty sure there are no Republican fish. I base this on the experience of all the anglers I know. They can tell you, all the fishies on their electronic fish finders are swimming to the left.😃