ID this creepy (and highly predatory) polychaete?

[Niffarious]

I've posted this video in a few places and have never been able to get an ID.

These worms absolutely decimated a tank of mine.

What they do:

They move like greased lightening. They build slime tubes they shoot through, and engulf their prey in the same slime and then eat it. And they work FAST. They seem to breed fast, and by the time I noticed them it was basically game over. Nothing ate them, they ate everything but most coral.

You're looking at a video of the reason I tore down my last marine tank.

Carnivorous polychaete worm - YouTube

Carnivorous polychaete worm - YouTube

I'd still love an ID...just to know what the heck I was dealing with.

[theinnkeeper]

What the hell, how did he even get in the tank to begin with? That things nasty

[chiefwonton]

there goes my dinner

[Niffarious]

What the hell, how did he even get in the tank to begin with? That things nasty

No idea where the initial infestation originated from. It seemed like they turned up overnight, but I hadn't introduced anything new (fish, liverock or corals) in ages at that point. So they were probably there undetected for quite a while. I suspect on some liverock at some point as either eggs or larvae...

[BelieveInBlue]

I believe that is some kind of sandworm or clamworm... Nasty buggers those things are; they have teeth and they bite, and boy does it hurt... They seem to make very good fishing bait though. I'd say that, if you have time, bring a few to the marine biologists at the vancouver aquarium or UBC and see if they could ID it for you.

[STANKYfish]

Kinda looks like a bristle worm....anyway i just pulled one of these out of my 14g biocube You have to have a firm hold and pull fast cause they can break off and split. Thats why i took the same worm out on two different occasions I did not find that they caused any damage to corals or livestock but more as a cleaner of unwanted food that was on the sand

[Niffarious]

@BelieveInBlue - I thought the same, but the head is very different and they appear to be more thin in body structure. Sadly I no longer have the aquarium that was infested (tore it down) and I did not preserve any specimens. Maybe I can get a partial ID from the videos if I contact them though.

@STANKYfish - they are polychaete worms but not bristle worms. There are no bristles, and they are not the harmless scavengers most of us are used to.

[gmachine19]

fireworm is what comes immediately to mind.

[reeferious]

these are just your regular bristle worms though i don't have exact specie name for them. they're attracted to anything that's in a weakened health state in your tank. A++++ to them for keeping your tank healthy.

[Niffarious]

Hey guys - maybe the video is not clear enough, but these are NOT bristle worms/fire worms. They do not have bristles. They have a distinct, flattened head with visible eyes, secrete what appears to be a poisonous mucous, and each segment has legs instead of bristles. And as mentioned, they are very highly predatory.

I'm very familiar with standard bristle worms, which are welcome in my aquarium. In contrast, I watched these particular worms attack, kill, and eat highly mobile hermit crabs.