[quote author=leeyiren link=topic=43.msg5615#msg5615 date=1269450539]
In the fish eye view from the water, why the image appears distorted? Any simple clear concise explanation? Thanks.
[/quote]

The first simulation was designed to help you understand why the image appears distored.
Please try to click the four corner of the object, the bending of the ray is different at different position.
The image was calculated from all points at the object. two rays emmitted from the the same point will refracted at different angle.  the interaction point of those two yellow line is the place where fish will see the image from that point.

You are welcomed to check out the following related applets.
[url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=378.0]An object under the water look differ! (Location and shape)[/url]
[url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=303.0]Where is the fish? (Refraction)[/url]