The DC Extended Universe has gotten a new breath of life thanks to the billion-dollar success of Aquaman, and despite the monumental effort by director James Wan, star Jason Momoa, and the entire cast and crew of Aquman, there's also been a lot of credit given to Zack Snyder, who had a major hand in shaping this onscreen version of the character.
When Batman v Superman first revealed Momoa's version of Arthur Curry/Aquaman, there was a lot of pearl-clutching criticism of how Snyder was making changes to the look and personality of Aquaman. However, as you can see in the concept art below, Zack Snyder did intend to bring the character closer to his comic book roots, and even had his own concept of what Aquaman's classic costume should look like:
As you can see, costume designer Michael Wilkinson did several concept art mockups of what Aquaman would look like in Justice League, including one concept of what the Snyder version of Aruthur's classic orange-and-green costume would be. Snyder's version of the suit goes for with much sleeker designs for accessories like the gauntlets, boots, and belt, adding touches of metallic gray for each instead of the traditional green for the gauntlets and boots, and gold for the belt. The Snyder version of the boots also have a shark fin element that has shown up in various DC Comics costume re-designs over the years. All in all, it has a lot more of a "fishy" aesthetic what we usually see for Aquaman - and apparently, the plan was for Justice League Aquaman to have much more of a lean muscle look than Momoa ultimately did in that film or his solo movie. For Justice League, Snyder finally opted to put Momoa in suit akin to the shoulder-pad armor design seen above, saving the full classic suit for the Aquaman movie.
James Wan's version of the Aquaman classic suit actually hews much closer to its comic book counterpart, with the bulkier gauntlets and boots, and golden belt. Momoa was also much more of a bulky beast when fitted into that suit - not that the fanbase seems to be complaining about it.
The DC Movie Universe continues with Aquaman in theaters now, Shazam on April 5th, Joker in theaters on October 4th, and Wonder Woman 1984 in theaters on June 5th, 2020.