I'll be honest, even writing about this thing gives me the creeps. I am not ashamed to admit that I am not a fan of this week's star of the show and I'm sure you'll agree that this is the thing of nightmares. The Bobbit Worm.
I think it's fair to say that nothing in this hobby invokes the feeling of dread and fear in the same way as when you suspect you have a Bobbit Worm in your reef. No doubt if you suspect the fearsome Bobbit you'll begin frantically googling images, comparing them to what you've witnessed. Anxiety builds as you run through all the scenarios in your head, images of you dismantling your reef tank rock by rock, carefully lifting your scape in-case it goes for your fingers until you eventually end up wrestling with some horrible monster of the deep before it hunts down your precious live stock.
Scary, right?
I know, I've been there. At least I've had that moment when I was starting off with my first reef tank. I saw a worm in the rockwork that I'd not seen before and my mind jumped to 'oh no.... what if it's a Bobbit? What am I going to do?' and then all the scenarios start playing out like a bad dream. Luckily, Bobbit Worms are quite rare. Probably one of the rarer pests you can get in your reef tank and whilst potentially difficult to remove, they're not impossible to get. The first thing to figure out though is whether or not what you're seen is actually a Bobbit. All too often I see comments on social media in particular, labelling every worm as a Bobbit. More often than not they're Bristle Worms, which look somewhat similar but are actually a helpful part of the Clean Up Crew.
So, let's have a close up look of a genuine Bobbit so that you know what you're looking at or rather not looking at (hopefully) in your reef tank!
The picture above is a zoomed in head shot of the main picture at the top of the Blog which has two Bobbits in the blue tray. Its not the best of photos I grant you but hopefully it'll do for the purpose of this blog. I did some research about the Bobbit prior to writing this and surprisingly there's not a lot of, if any, identification guides out there for the reefing community so it has been difficult to confirm my six identifying features. But, that being said, here are six features that I observed which you can use to help identify a Bobbit;
1. Colour. Compared to all the other worms I've seen in my reef tank, Bobbits are a very dark, almost black colour all over their body. The images I've seen online show Bobbits as being a light brown/sand colour. This could be down to lighting and photography but the five that I've seen in the flesh were all very dark.
2. Iridescence. The top of the Bobbit's head has an iridescence to it. You can't see it in this photo but Iridescence is like when you see petrol or oil on the road in daylight, it has that slick multi-coloured appearance. I can't say I noticed this on the body but I definitely noticed it prominently on the head and there are some online images of other Bobbits which confirm this.
3. Size. Bristle worms are most often wrongly identified as Bobbits. I've seen some big Bristle worms but none have been bigger than 15cm. Bobbits however can reach 10ft in the wild. Now I'm not saying that you're going to have a 10ft Bobbit on your hands but they can get big. They're very reclusive as well so chances are if you did have one in your reef tank you probably wouldn't see it until it was larger, say 1ft long maybe? For context, the two Bobbits in the main picture were at least one and a half foot long each if not longer. The third smaller one from that day which isn't in the photo was about 15cm.
4. Tentacular cirri. If you look at the zoomed in picture of the head you can see some antennae/tentacles protruding forward. These are called Tentacular cirri and whilst they are not exclusive to the Bobbit worm, they are prominent. Bristle worms do not have the same prominent tentacular.
5. Chaetae. If you look at the zoomed in picture again you can see on opposite flanks of the Bobbit there are spikes with hairs around them on each segment of the body. These are called Chaetae and again, this is not exclusive to the Bobbit but the chaetae on the Bobbit have prominent single spikes which are then surrounded by much smaller hairs/bristles. The Bristle worm's chaetae however are like clusters of hairs/bristles, hence the name Bristle worm.
6. Mucus burrow. I didn't get a photo of this and in hindsight I wish I had. Bobbit worms create mucus burrows in which to live. These look a bit like funnel spider webs. I expect they make these burrows because the Bobbit lives in the sand bed and needs something to stop the substrate collapsing in on itself. Interestingly, the three Bobbit worms found here weren't in the substrate but in a very large and very old Stylophora colony. There was only one fish in the large sump tank so I'm assuming they were surviving on smaller amphipods, shrimp and crabs and so took up shelter in this colony to be closer to the food source.
Those are the six main features that I observed and should help you identify a Bobbit or at least figure out if your suspect is a Bobbit or a Bristle.
As for how to remove a Bobbit worm from your reef. I'm afraid the only way to get them out is to go hunting. You'll need a long set of tweezers/tongs (maybe two), a red torch, bait and patience. The Bobbit is nocturnal so you'll have to wait till lights out, wait and watch. Find where the burrow is and then you'll have to encourage the worm out of the burrow with the bait which is where the first set of tongs come in and then when the Worm is fully if not mostly out of the burrow you can use the second tongs to grab the body of the worm and lift it out. The reason you have to wait until its mostly out is because they can separate and if you don't have most of the worm you'll lose part of it and you'll have to go through the whole process again.
Credit where credit's due though, the Bobbit is a highly accomplished ambush predator with no predators of its own (once it gets big enough of course). But, as I said at the start of the blog, they aren't common in the reef aquarium and when I say I've seen five, that's probably five more than most reefers so don't worry too much. Chances are if you've seen a worm in your reef it's more than likely not a Bobbit, it's probably a Bristle and despite what many on social media say, Bristle worms are a great part of your natural clean up crew and won't go after your livestock. If in doubt, get a good quality photo or two and bring it down to the shop and the team can have a look to help identify it for you.