But boxfish, when alarmed or being eaten, secrete their own toxin in a slimy mucus that oozes from specialized skin cells all over their body. The clear, toxic "ooze" immediately disperses into the water , creating an invisible cloud of death surrounding and trailing an inevitably spooked little boxfish.

How toxic is a boxfish?

While Boxfish and Cowfish cannot sting you, they can exude a toxin from their skin which can poison an entire saltwater aquarium in just a few seconds.

Are boxfish good to eat?

To avoid confusion with these poisonous relatives, some people avoid eating boxfish despite their being good for food. ... Like other species of fish, when disturbed boxfish can secrete molecules known as icthyocrinotoxins or ichthyotoxins—literally, fish poisons—from their skin.