I beat Duke Fishron pre mech on Master mode

Here's the gear that I forgot to show in the video:

Adamantite mask
Frost breastplate
Mythril Greaves

Bundle of balloons
Magic quiver
Stalkers quiver
Ranger emblem
Brain of Confusion
Star veil
Charm of myths

Daedalus stormbow with ichor arrows
Uzi with crystal bullets

Everything reforged to menacing

The last three survivability accessories are there to compensate for my skill issue but they can be replaced with molten quiver, stinger necklace, and putrid scent for even more damage.

I made lots of silly mistakes that could be avoided but all in all, a very fun fight.