"two horned" hitchhiker on valida acropora

laurenlin123 · Oct 3, 2017

Hi everyone,

I am new to saltwater aquarium. So far I have only got three corals in my nano tank. The latest addition is a valida acropora (about 3 inches tall). I have noticed there are two tentacles sticking out from one of the coral tip, after some googling online, it seems to be a spionid worm --this picture is not mine, it is originally posted by someone named Sczlars from another forum. Mine looks exactly the same.

It looks so creepy to have it on my coral and I don't want it to spread. I tried to catch it with a pair of tweezers, but this fella is way too quick. I have been on a tweezers snap battle with him for two days! At one point I snapped the coral tip by accident, I noticed that there is a hole in the middle of the coral skeleton, and this bugger seems can travel through it. It appeared again from another tip (another tip with no polyp). I am so fed up with this bug, I don't think I can ever be quicker than it and catch it by the tentacles. I am worried I am going to destroy the entire acropora ....

Is it dangerous? Can it reproduce on its own? What would be the best way to get rid of it?

Big thanks, folks!

nautical_nathaniel · Oct 3, 2017

It is a type of worm from the Spionidae or the Chaetopteridae genus, generally harmless but can reproduce quite quickly. Here's some more information on them:

"The similarity of the body regions is not the case with the chaetopterids, and at least one member of this family may be very abundant in reef tanks. This abundant worm is placed in the genus Phyllochaetopterus. Phyllochaetopterus individuals build a tube out of "hardened" mucus in which they cement sand grains. These tubes can be up to an inch or so in length and are about the diameter of a thin piece of pencil lead. They will be oriented vertically in the sediments or occasionally found filling pre-existing holes in rocks. The worms themselves are quite small, less than a quarter inch long; in fact, in most cases less than a tenth of an inch. Consequently, their typical tube provides them with quite a spacious home. The tentacles are often five to ten times the length of the rest of the worm, and when examined with a hand lens or good magnifying glass, the various regions of the worm may be seen to have distinctly different appearances."

"Phyllochaetopterus is generally a benign member of the detritivore group found in reef tanks and they are pretty good scavengers; any particulate material that strikes their tentacles is pulled into the tube and eaten. However, they are gregarious and reproduce well in reef tanks. These two properties may, in time, cause some problems. The worms can form quite large mats with literally hundreds to thousands of tubes all cemented together. These mats quite efficiently exclude other worms from the area, and can seal off the sand bed surface. This, in turn, can cause the emigration of other animals out from under such a patch, which can result in the cementation of sediments under the patch and the failure of the sand bed biological filtration under the patch of worms. Such worm masses need to be periodically broken up or removed from the system, otherwise they may cause the complete failure of a deep sand bed. The reproduction and subsequent patch growth can occur with surprising speed. In a 60 gallon hex tank I once had, I introduced some of these worms and, within about three months, they had literally paved the sand bed surface with their tubes. I attempted to remove them all, and it was not an easy task."

Source: http://reefkeeping.com/issues/2003-05/rs/

laurenlin123 · Oct 3, 2017

Thank you for the information! Good to know that they are harmless, but not good that they can reproduce quickly---I've only got one though.

Ahhhh....what to do?! I was tempted to snap off that branch of my acropora, but worried it might travel fast and I'd lose a a big chunk of coral for nothing.

nautical_nathaniel · Oct 3, 2017

laurenlin123 said:
Thank you for the information! Good to know that they are harmless, but not good that they can reproduce quickly---I've only got one though.

Ahhhh....what to do?! I was tempted to snap off that branch of my acropora, but worried it might travel fast and I'd lose a a big chunk of coral for nothing.

Do you have room for another fish, a member of the Halichoeres genus of wrasses may be able to slurp it out as well as control any other small pests you may introduce later on down the line. It may take it a couple of tries, but I know my Hoeven's/Melanurus wrasse would have that worm out within a week!

laurenlin123 · Oct 3, 2017

pensacola-aquarist said:
Do you have room for another fish, a member of the Halichoeres genus of wrasses may be able to slurp it out as well as control any other small pests you may introduce later on down the line. It may take it a couple of tries, but I know my Hoeven's/Melanurus wrasse would have that worm out within a week!

Wish I could have this awesome fish. But I have only a nano tank, 80L (21 gallon), perhaps too small for it?