This is kind of a game, but more of a participatory project.
We all know that Aquaman might just be the worst superhero ever. His powers only work in water, he's only well-known because of the Superfriends and his entire character is pretty much a DC version of Marvel's Sub-Mariner. Everyone hates him.
So let's make him better.
Your mission, if you choose to accept it, is to make Aquaman less of a suck-tacular character. Maybe something that'll let him leave the ocean. It's up to you.
I'll start: I feel like the most logical extension of his powers would be to give him control of not fish, but the water itself. In the ocean, he could use it to manipulate his surroundings, maybe create whirlpools, but that's not all. Aquaman could also manipulate the water vapor in the air, and the H20 present in plants, animals and enemies.