Spawnout

Are you sure about that last post? Sounds a little far fetched to me, but I honestly can't say with certainty.

One thing is for sure, though.... salmonids have an iris. It may not be blue or brown like yours and mine, but it's there. Kind of a silvery gold color but sometimes a darker gold. If this piece of eye anatomy is present, it must serve some useful purpose.... namely as a diaphragm to control the absolute amount of light allowed to pass thru the pupil (the dark hole in the middle of the iris), just like in our own eyes.

I have never examined a living piscine patient's pupillary reaction before (never had a reason to) but I can assure you that the pupil has the ability to constrict.... just look at any dead fish photo for proof. The pupil in a living fish almost has a fat tear-drop or watermelon-seed appearance. The pupil in a dead fish is perfectly round, very small and beady, accentuating its lifeless appearance.

The real question is whether the pupil constricts in a living specimen. Will have to check that one out. Problem is I have to catch a fish first... been on a long drought for far longer than I care to admit.