Male or Female trout, how do you tell the difference?

Female trout have larger pectoral fins…that one’s easy!

When you take it out of the water… if it’s mouth is closed, it’s a male; if it’s mouth is open, it’s a female.

The females go for the flashier flies

What have I done? My brother always told me the people on this forum were a wealth of knowledge. Next time I catch a trout, I’m gonna probe and study it more than the aliens did my cousin.

It’s hard to tell before they are sexually mature but here is a photo that may help a little. These are two brook trout, caught in the same water, same time…similar in size.
The female on the left has a shorter snout and upper jaw line then the fish on the right. The male has a longer face, with a slightly more streamline look to it.

hmmm… I don’t like the new way photos are handled on here. I guess you’ll have to click “attachment whatever” .

I cannot resist the one those of us who have worked with oysters have routinely been asked:

Neophyte:“Can you tell the sex of an oyster?”

Biologist: “Yes”.

Neophyte: “How?”

Biologist hands an oyster in-the-shell to the Neophyte and tells them to hold it to one of their ears and shake it.

Neophyte does as told.

Biologist asks: “Did you hear anything?”

Neophyte: “No.”

Biologist: “It’s a female!”

Neophyte: “How do you know?”

Biologist: “If it was a male you would hear it’s n–s rattle!”

Works every time!

Cheers!