Synanceia are primarily marine, though some species are known to live in rivers. Its species have potent neurotoxins secreted from glands at the base of their needle-like dorsal fin spines which stick up when disturbed or threatened.[3] The vernacular name of the species, the stonefish, derives from the stonefish's ability to camouflage itself with a grey and mottled color similar to the color of a stone.[4] Swimmers may not notice them, and may inadvertently step on them, triggering a sting. When the stonefish is disturbed, it may inject an amount of venom proportional to the amount of pressure applied to it.[citation needed]