Brocken Inaglory (CC BY-SA 3.0)
Common Bristleworms
Eurythoe complanata and relatives (family Amphinomidae)
Scavenging detritivores with no jaws; they eat leftovers and dead matter and cannot kill healthy livestock or corals.
Identification
Segmented worms in pink, brown, grey, or tan, sometimes iridescent, with fine tufts of pale bristles running along both sides of a slender, pencil-thin body. Usually only the front few centimetres show, with the rest anchored in rockwork; they emerge at night, at feeding time, or when rocks are moved. Handle rock with gloves — the bristles of any bristleworm irritate skin like fibreglass splinters.
Often confused with
The bearded fireworm, Hermodice carunculata, a genuine coral predator. Width and bristles separate them: the common bristleworm stays slender with fine, sparse side bristles, while Hermodice grows stocky as a finger, carries dense, fluffy white bristle tufts with red gills, brighter orange-red colour, and a prominent red feathery caruncle on its head. A thin muted worm scavenging at night is the common cleanup kind.
Natural predators
No natural predators are listed.
Field notes
Core members of the cleanup crew that sniff out uneaten food and dead organisms deep inside rockwork where nothing else reaches. Tanks nearly always have them; a visible few at feeding time is normal, and population size tracks how much food is available.