Fireworms (bearded fireworm)

Identification

A thick, flattened segmented worm up to about 15-30 cm, coloured olive to purplish-grey with orange-red gill tufts along each segment and dense bundles of chalk-white bristles. The head carries a conspicuous fleshy, reddish, frilly crest called a caruncle — the single best identification mark. Unlike most hitchhiker worms it may roam in the open, and under blue or UV light at night it can fluoresce green-orange.

Often confused with

Common bristleworms such as Eurythoe complanata, which are also amphinomids with white bristle tufts and cause most false alarms: they are slimmer, lack the prominent red caruncle on the head, and scavenge dead matter rather than hunting living coral. If the head crest cannot be found, the worm is very unlikely to be Hermodice.

What it targets

Stony corals, gorgonians, hydrocorals such as Millepora, anemones, and opportunistically sponges, snails and urchins. It everts its mouthparts over tissue and digests it in place, leaving bare skeleton patches.

How it spreads

Hitchhikes on Caribbean and Gulf live rock and live coral shipments, which is also why it stays relatively uncommon in tanks stocked with Indo-Pacific rock. A torn worm can regrow from fragments, so careless removal can make things worse.

Control (safest first)

Baited bristleworm trap at night: the method most sources recommend; be patient, because the trap will catch harmless worms and other scavengers first. Never handle the catch barehanded. Tongs removal only when the whole worm is out in the open and can be taken in one piece: a worm torn in two can regrow from both halves. Thick gloves are mandatory; tape lifts bristles out of skin, and hot water soaks are the standard first aid keepers pass on. Remove the hiding rock and flush the worm out outside the tank when trapping fails, since large specimens wedge into very tight crevices. Biological control is thin: some Halichoeres and Pseudocheilinus wrasses pick at fireworms, and the crown cone Conus regius eats them in the wild but is venomous, specialised and a poor aquarium choice — do not add a cone snail to solve a worm problem.

Natural predators

• Melanurus and other Halichoeres wrasses
• Sixline wrasse→

Field notes

A Reef2Reef keeper who pulled seven suspect worms from a week-old tank put them in a container for identification; close inspection showed no caruncle, the worms were judged common Eurythoe, and they went back into the sump as cleanup crew. Reef2Reef members pushing back on a bristleworm eradication post argued the worms in the photos were scavenging a snail that was already dying, and reserved real concern for confirmed Hermodice, which hunts living coral. WetWebMedia answers show the same split at expert level: one correspondent with a suspected Hermodice was advised the group is mostly detritivorous and reports are often misread scavenging, while identification guides on the same site still single Hermodice out as the coral- and gorgonian-eating exception.