He was a healthy 10-month-old until the day he ate swordfish. Afterward, his mother noticed an intense smell like rotting fish, coming mostly from his head and hands. It came back when he ate other kinds of fish, and a two-month fish-free diet made it disappear. When hake and then forkbeard were added back at 12 months, so was the odor.
Pediatricians at hospitals in Aveiro and Porto, Portugal, traced the smell to trimethylaminuria, better known as fish odor syndrome. Their report, published in Cureus in February 2025 when the boy was 3, ends differently from most accounts of the condition: by 19 months of age, he was eating recommended portions of fish without the smell coming back.
