Debatable as to whether he's abusive but Triton argues with Ariel a lot and destroys all of her prized possessions which could be triggering if you've been abused.
Ursula, as seen in the original animated movie, has the power to see what Ariel is doing so she can plan her next actions accordingly. She uses what looks like a crystal ball.
Ppl that have arachnophobia can sometimes be afraid of crabs. So just be aware that Sebastian is a realistic crab with all the legs and movements. I suggest googling a picture of him beforehand so you can see whether or not his appearance disturbs you.
Sebastian is a crab which, as mentioned in the “Are there spiders?” comments, can be triggering to some people who find bugs discomforting. He’s pretty realistic, but also very clearly CGI.
Ariel can’t breathe underwater when she’s first given legs, learning the hard way that all humans lack the ability to breathe underwater. It only lasts until the iconic “hair flipping at the surface” scene.
Not exactly but can be considered cheating by some. Ursula disguises herself in order to prevent Ariel from fulfilling her side of the agreement. Ursula uses Ariel’s voice to trick Eric into thinking she (Ursula) saved him, and nearly proposes to her, but the truth is later revealed.
There are sentient sea creatures and Sebastian mentions said creatures being eaten by humans, but no people are eaten and any meat or fish being eaten was not shown to be sentient.
Eric coughs up water after nearly drowning, but it was very brief and it was only a little. It wasn’t intentional either, he just obviously needed to get the water out of his lungs.
There are storms in the beginning (boat scenes) and end with lots of lightning for dramatic effect. I found it to be an eyestrain and may trigger epileptic seizures.