Trivia: When King Triton enters the concert hall and passes over the audience, you can see Mickey Mouse, Goofy and Donald Duck sitting among the audience. (00:03:33)
Revealing mistake: When we first see Max, his paws are leaning on a balustrade and become transparent. Though it may seem like it's an optical effect because they're in the shadows, the next angle shows them fully lit and opaque.
Continuity mistake: After becoming human, Ariel swims and rest on a floating rock amidst the sea. A frame later she is laying on a rocky wall by the shore.
Continuity mistake: The bookmarks in the Minister's bible keep changing colour between shots.
Continuity mistake: When Grimsby is presenting the statue of Eric, the huge ribbon around it disappears between shots.
Factual error: When Louis the cook chases Sebastian in the kitchen, Sebastian hides in a cabinet full with plates and bowls which reflect the rabid cook's image. However, in both real and mirror-reversed image, his actual right arm (with the mallet) is raised up high. (00:54:15)
Continuity mistake: When Ariel is crying and Sebastian comes to comfort her, there's a vase, two planks and a small bottle behind her. When the angle changes, every object is different, even the area looks much wider.
Continuity mistake: When we first meet Max, his front paws swap from white in the front angle, to grey in the angle shot from behind.
Continuity mistake: The lettuce under which Sebastian later hides, wasn't on the table in the first place.
Continuity mistake: When Ariel spies the guys on the boat, she is under an arched window. Depending on the angle, the space is made of 3 blocks of wood, or 2. This keeps changing randomly all the time.
Continuity mistake: During the eels scene, when Ariel is crying, the stone she lays on is a single stone laying almost flat on the sand; then swaps to a double stone, and when she sends the eels away it is a single stone though way steeper, standing upright.
Continuity mistake: Eric's statue changes between shots, notice the position of the right fist.
Continuity mistake: After Ursula eats the shrimp, when the angle changes the rest of the shrimps in the shell become some sort of white beans.
Chosen answer: They are all throughout the film but the biggest one is when Eric is steering the ship to stab or skewer Ursula.
Disney-Freak