Question concerning pressure treated wood and ponds

You hear all kinds of things good and bad concerning the use of
pressure treated wood in and around fish ponds. Of all the state
parks and recreation areas I have been to or sen I don;t think there
is one that does not use pressure treated lumber to build piers,
walkways and such arond the water. I want to build a 3' wide walkway
around the outside of my koi enclosure and also add a gazeebo coming
off the long walkway that extends further out into the pond. The way
my enclosure is built ifyou look at my website images, is the nicest
view is from the water side looking in towards the land side, so a
walkway would certainly give a better overall view. Been considering
using 4 x 4 PT posts for supports to hold PT lumber for the
decking...

Any pros and cons concerning the use of PT wood for such a project?

I certainly can't afford galvanized steel or aluminum stucture, or
even a cedar or redwood enclosure. Walkway would be about 60 lineal
feet total with another 8 x 8 or so platform / deck areas mounted off
it towards the center of pond.
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