What is the white string hanging from my fish?
Ava Hudson
Updated on May 21, 2026
When the fish hasn't consumed anything in a day or two, you would then notice a slimy, white string hanging from the fish hinting at you that its stomach is empty. The white poop isn't really what it seems; it's just mucus coating passing out of the fish's body, other times also known as an empty fetal cast.
What is the white thing coming out of my fish?
White fish poop is a poop with no food in it.In order to help move things along, our guts are lined with mucus-producing cells to help things slide through. Without this lubrication, you'd never be able to pass a single poop, swell up and die. Fish have the exact same cells in their guts!