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Bristle worms in your reef tank…so what?

Americans and I’m assuming most Europeans, have a natural dislike of worms. They’re creepy, sometimes slimy, and they move in what seems an unnatural and distasteful way. I remember going fishing when I was a kid and putting the red earth worm on my hook. As soon as the sharp end of the hook would penetrate the worm’s flesh it would wiggle vigorously and inevitably turn its head toward my hand as if it were trying to bite me. I knew even then that earth worms didn’t bite, but I still hated the odd little way the worm moved.

People are killing bristle worms and they shouldn’t be!

Soon after a tank is set up, if it’s done right that is, worms will begin to appear, as if by magic, all over the tank. Of course it isn’t magic, they’ve hitchhiked, like so much of the other life we’ve discussed, on your live rock and live sand, or even the corals themselves.

Among the more common worms are a kind known as bristle worms. Since I do a lot of research and reading on message boards and other blogs I’ve come across a disturbing trend, the killing of bristle worms. This bothers me because it is being done out of ignorance.

Good Worm

Concerning bristle worms, Dr. Ronald Shimek in his book, The Coral Reef Aquarium
wrote, “The most common worms that appear in our systems are fireworms, or Amphinomids. These typically are pink, and each segment has a large evident tuft of white bristles on each side.” Based on this description, and what I have in my own tank, this is the very worm I have read time and time again being killed by aquarists in some sort of a panic. Shimek goes on to say, “Although one species of fireworm occasionally preys on soft corals, it is almost never seen in reef tanks. Most of the species that show up in reef tanks are beneficial scavengers.”

Hermodice Carunculata is the coral-eating fireworm that may “occasionally” dine on our soft corals. How can an aquarist identify this animal? Going back to Shimek, but this time one of his other books, A PocketExpert Guide to Marine Invertebrates
, we read, “It is generally smaller than Eurythoe and can be distinguished by its reddish to silver-gray body color, the presence of blood-red frilly gills above each tuft of chaetae, and the presence of frilled appendages (the “beard”) on the back of the head.” He reiterates in this book, “Fortunately, this species is rare in marine reef tanks and is probably collected only infrequently.”

Bad Worm