Recently, I saw this image, and later, this image, which inspired me to think about the culture of merpeople. I've got quite a lot worked out, but I'd appreciate hearing other's ideas. In particular, I'm looking about laws and government, and how they might vary from our own.
Some crucial aspects about the merfolk are
Human-level of intelligence
Near the human level of technology (exception is medicine)
Magic is rare but not nonexistent. The types of magic are controlling air, controlling heat, and healing.
Interactions with humans only happen once every couple of months and are mainly trading. The relationships from one species government to another are not hostile nor exactly friendly. The people are very interested in the other species.
The merfolk have a society that is very focused on equality.
Their eyes, nose, teeth, and hair are all designed for an underwater environment. Their hair isn't even hair, it just appears like it, and is used for mothers to carry their young. It can move independently.
The subspecies of merpeople are (along with the generic merfolk)
Tropical Reef Island Coastal Coldwater coastal (mainly European) Warmwater coastal (only live in water that is warm year-round) Estuarian Freshwater River Lake Waterfalls Swamp Kelp Forest