Pahutoxin, formerly called ostracitoxin, is a neurotoxin present in the mucous secretions of boxfish (Ostraciidae) skin, while under stress.

[1] It is an ichthyotoxic, hemolytic, nonpeptide (which is relatively unusual, although similar to tetrodotoxin in this way) toxin.

It is heat-stable and non-dialyzable, that is, foamed in aqueous solutions, and is toxic to various biological systems.

It is toxic to other boxfish as well and looks like red tide and sea cucumber toxins in general properties.

Members of the family Ostraciidae secrete an ichthyotoxic mucus from their skin when stressed or disturbed.