The Bobbit Worm: Your Saltwater Tank’s Loch Ness Monster

PetGuide logo

Deep in the Lochs of Scotland, there is an elusive creature many have claimed to see for centuries, but no (credible) evidence has ever surfaced. Is it a mythological creature, or does it really exists? What if we were to tell you that it does exist – in fact, it may be lurking beneath the surface of your saltwater aquarium, quietly resting, growing, until BAM! It emerges, scaring the bejebus out of you!

Alright, so it’s not a giant mythological amphibian – but the Bobbit worm is every bit as creepy. It’s a saltwater invertebrate that lives deep in the ocean’s floor, only exposing a few inches of its body to attack passing fish and other prey. It strikes, injecting a paralytic toxin into the unsuspecting fish, so the worm can kill its prey nearly instantly. The Bobbit worm gets its name from the Lorena Bobbit scandal, and if you don’t know who that is, I’ll give you a minute to do a Google search… yep, that really was an international scandal!

Related: Expand Your Saltwater Tank With a Refugium

In an aquarium, the Bobbit worm presents quite the mystery to the aquarist, who wakes up to find fish missing, maimed, or shredded without an obvious reason as to why. I’ve heard of this happening in several public aquariums before, and the only way to find the cause of the deaths was a total tear down of the tank, thus revealing the rather large and creepy culprits.

Bobbit worms hitchhike into tanks on live rocks as tiny babies; they then burrow into the substrate and grow until they are a few feet long. Bobbit worms found in the wild have grown up to 10 feet in length. Like some of the world’s most dangerous critters, Bobbit worms are actually quite beautiful… from a distance. They feature a golden metallic hue that reflects many of the rainbow’s colors.

Related: Choosing Soft or Hard Coral  

Ridding an aquarium of a Bobbit worm isn’t an easy task, largely because by the time someone realizes there is a problem, it’s far too large to just scoop out. More often, the aquarium owner knows that there is an issue, but has no idea what it is. The only way to remove this creepy sea dwelling creature is to tear down the tank and remove the worm. Do not attempt to cut the worm into pieces, as they are segmented, and you will literally multiply your problem with every cut.

Some people have tried to eliminate a Bobbit worm infestation by pulling the worm out with large tweezers. This can prove both difficult and risky as Bobbit worms will weave their bodies through the holes in coral and pull back with surprising strength. Another risk with this method is that if you do manage to grasp the worm, it could break – then you have two Bobbit worms wrecking the place. Others have tried to rid their tank by hand feeding the pests dog wormer, super glue, and crushed glass… but without avail. The Bobbit worm lived on.

The next time you find yourself admiring a beautiful reef, just remember what could be lurking beneath the surface of the sand, waiting for its chance to pluck off saltwater fish one by one… and nobody knowing the wiser.

summerSummer Davis is the mom of three kids, four dogs, and several tanks of fish. She boasts a passion for all animals, whether they are in the water or on land. This fish aficionado has kept many different species in her time, but holds a special place in her heart for wild and domestic bettas. When she’s not talking about fish, Summer “spins” her extra time as the director of a baton twirling organization.