Here is what you will need to make a homemade Aquaman costume for Halloween. Arthur Curry/Orin costumes are easy to make with DIY ideas. Get some great ideas including how to make a trident here.
Aquaman costume tutorial
San Diego Comic-Con 2015 Cosplay - Aquaman
Aquaman Shoulder Armor by rassaku
Dragon Scale Armor Gauntlets Knitted Scale Maille Elbow Length Gold Dragonhide Custom Made. via Etsy.
Aquaman @ New York Comic Con 2012 (NYCC). Who says scales aren't badass?