Crawfish

[the_donger]

The blue would be the result of molting in the last couple of weeks. The large ones are the first to come out because their size helps them regulate their body temperature more efficiently than the smaller craws can.

[Fishin is life]

A lot of crawdads actually have that blue coloration....hence the reason a black/blue jig works....just try to match the hatch

[timmbur22]

Thanks for your replies fellas.

I think I'll add just a touch of blue to the back of some of my crank baits

[zx150]

Does anyone know the molting color cycle for a crawfish?

[Carter1]

I googled: crawfish molting color cycle. Then I got a page with a bunch of headings to click on. The one I found that I think will answer your question is; outdoor forums:crawfish.
It is a discussion board on the Bass Pro Shop site.
Hope this helps.

[timmbur22]

Actually, now that I think about it......the color I noticed was not Blue.........it was pure TURQUOISE............

[timmbur22]

It appears they were not molting yet, but forming a blueish exoskeleton underneath their old brown one. They are getting ready to molt. The explanation of bigger crawdads being able to handle colder tempatures makes good sense to me also. Here's a interesting link:

http://www.billwarman.com/crawdad.html