Peanut Worm?

Hello all!

I have quite a few of these guys in my tank we picked up from a fellow utahreefs goer and I wasn't quite sure what they were. When we first were moving the tank and sand and such these guys were curled up along the top of the sand bed after being put in buckets. I assumed they didn't make it, but once we refilled the tank and got everything going they came to life. They buried into the sand and now stick out tentacles with two black ones (reminding me of pinchers in a way). I started to wonder if it was a predatory worm, but I wasn't sure.

So I'm here asking you experts for help!

I shoveled one out of the sand bed. He wasn't happy and brought his tentacles in a bit.

Here is a pic of what he looks like in the tank with is mouth wide open. Sorry it wasn't the best of pics, they blend with the sand bed pretty well and this guy was wedged between a rock and the sand.

Big arrow is pointing to his head/mouth (lighter circle with the two dark black lines are part of his mouth?) and the smaller arrows pointing to his tentacle type things around his mouth. They are almost anemone-like.

I can't find any pics of a peanut worm with his mouth extended the way these guys do... your help is much appreciated!

I hear mixed reviews on Medusa Worms. Not sure yet if they really leave the sand bed to move around like some have said they do. Most are in the same spot they always are. :/

I'll definitely research more about Medusa worms to see if that's what they could be!

I second that it's not a peanut :)

have you tried to touch it does it retract quickly that looked like a type of aptasia to me

Shawn, am I correct in thinking that this is because they die and release their toxins rather than because of any actions on their part?

Still wondering if I should be leery or not of these guys. They definitely are the smaller kind (I say that now ) And it's not the same sort of 'medusa worm' sold at some fish stores. Conflicting tales of them killing/not having the parts to kill makes me still up in the air. It would be quite a task to get all of them out and re-disturbing the dsb and such.

      I  disagree with WWM they are TOXIC.  If they die they will release toxins and kill your fish, it is however harmless to Corals.  I had a hitch hiker wipe out all of the fish after it fell into a Carpet Anemone.  It also killed the Anemone.  These are IMO worse than Sea Apples.  I've heard the same from many different people over the years, so believe who you like but it seems not worth it to me.  Here is a quote from Ron Shimek, Reef Invertebrates Book -Have the potential to cause tank"wipeouts"

      Welcome to the world of Reef Tanks,  you will always find tons of opinions.  Most are lip service and some are backed up with practical experience.  As far as the Ecosystem?  There are a ton of things that are a part of the Ecosystem  that do harm to you reef tank.  Because it exists does'nt mean you want it in your tank.

     Its always your choice to choose your advice.  There is a difference between "book smart" and "street smart".

jen! wrote: Still wondering if I should be leery or not of these guys. They definitely are the smaller kind (I say that now ) And it's not the same sort of 'medusa worm' sold at some fish stores. Conflicting tales of them killing/not having the parts to kill makes me still up in the air. It would be quite a task to get all of them out and re-disturbing the dsb and such.

You have brought up a good point for discussion. One thing to think about here is that the suggestions that any hobbyist can give is limited to their own experience. It's important to know the experience and knowledge level of the hobbyist giving the advice.

The LFS have experiences that hobbyists never encounter. Typically LFS aquarium systems are different than our home reef aquarium. They have fish running through their tanks constantly. Our animals stay the same. Fish that come into a LFS are often not even out of their stressed state when they get sold.

Assuming that you are relatively new to the hobby, I would suggest three things:

1- Take what you hear/read with a grain of salt. Use it as you feel is best for your tank and situation.
2- Consider that in this circumstance, these worms came from an established tank that probably never had any problem with them.
3- Recognize that 99% of all organism species in our tanks are a good and necessary part of the ecosystem. Each tank is different and each has it's major forms of life. It's entirely possible that in your care the environment of this tank may be different enough that these worms may not even survive to reproduce, so whether they are really good or possibly bad will be a moot point.


BTW, I noticed that you mentioned the disturbing of the sand bed. After many years of experience, I have found that it is best to disturb a sand bed from time to time. Just like a storm on the ocean that stirs everything up, our tanks do best when there is a little storm now and again. In fact the detritus that collects in the sand bed, when allowed to puff up into the water column, is food for coral. There are several ways to do this if you are interested.