FirewormsAmphinomidae

Fireworms are marine polychaete worms with elongated, segmented bodies, typically 2 cm (0.8 in) to 30 cm (12 in) long. Their most distinctive feature is paired tufts of white, needle-like bristles (setae) on the sides of each body segment. These bristles are visible and prominent, readily embedding in skin on contact and delivering a neurotoxin that causes a strong burning sensation, from which their common name derives. Body colouration varies widely, often including shades of red, orange, yellow, or green, sometimes marked with stripes or spots.

They inhabit coral reefs, rocky coasts, and seagrass beds, found from the intertidal zone down to around 40 m (130 ft) deep. These worms are commonly observed crawling slowly over hard substrates, among coral branches, or within crevices during the day. Fireworms are primarily scavengers, feeding on detritus and carrion, but also prey on small invertebrates and coral polyps.