They would probably start off being a bit cautious of each other. Harry would be intrigued by Arthur's unique powers and his connection to the ocean. Arthur, on the other hand, would be curious about Harry's magic. They might exchange stories about their respective worlds at first, like Arthur telling Harry about Atlantis and Harry sharing tales of Hogwarts.
Maybe Arthur Curry is sent to Hogwarts on a mission. He has to learn magic quickly to blend in and help solve a mystery that involves dark wizards trying to steal Atlantean magic. Along the way, he befriends Harry Potter and they exchange knowledge - Arthur teaches Harry about the ocean and its secrets, while Harry shows Arthur the ropes of wizardry.
In the main comic storylines, Aquaman is not gay. However, there might be alternate universes or special editions where his character could be portrayed differently, but that's not the norm.
The story of Aquaman involves his struggle to find his place in two different worlds. He faces challenges from both human and Atlantean enemies as he strives to unite the two and bring peace. His powers and connection to the ocean play a crucial role in his adventures.