Another hitchhiker!

[Nick Steele]

Okay so I had an idiot moment in my tank last night where I left the flow off after feeding for the night. This morning everything was fine but I see this long worm crawling across my sand!!! I get it out and I notice it’s not like a fireworm or bristleworm. It’s more like those earwig things on land! Below is a pic. It has a split tail section which is unknown to me.

It’s sitting in a cup currently just in case it’s a good guy but I doubt it with the way it looks/swims. When getting it out it wiggle like a flatworm and swam in the cup (super weird!!!) I’m guessing it came from my gulf live rock as I’ve dipped all my corals and found dead/stunned hitchhikers on all!

 

[fishguy242]

#reefsquad

 

[SnazzyUrchin792]

@ISpeakForTheSeas

 

[Rjukan]

Looks like some type of bristleworm to me, but I'm not very knowledgeable lol.

 

[ISpeakForTheSeas]

Yeah, this is a kind of bristleworm (Polychaete), though the bristles/paraodia are quite unique; I can't place it offhand, but I'd guess (quite possibly inaccurately) that it's from one of the three following families:

-Nephtyidae; these are predatory toward other worms, sedentary inverts (like small clams, foraminifera, etc.), possibly pods, etc. - These shouldn't be a threat to anything large (like fish and inverts we put in our tanks) except for possibly bivalves (like clams).

-Microphthalmidae; there doesn't seem to be much (or any) info on their feeding.

-Pilargidae; there also doesn't seem to be much (or any) info on their feeding.


The most I feel confident in saying is that it's most likely from the taxonomic suborder, Nereidiformia. Also, if you haven't seen any problems in your tank that a predatory worm may have caused, then the worm is most likely harmless/beneficial for your tank.

With regards to the swimming motion, some species of polychaete do swim regularly, and many species swim as epitokes (the reproductive stage of polychaetes).

The swimming is unusual for bristleworms that aren't epitokes, but it's not unheard of. Cool to see the undulation as it moves!

 

[Nick Steele]

Looks like some type of bristleworm to me, but I'm not very knowledgeable lol.

Idk it swam like a water snake

Yeah, this is a kind of bristleworm (Polychaete), though the bristles/paraodia are quite unique; I can't place it offhand, but I'd guess (quite possibly inaccurately) that it's from one of the three following families:

-Nephtyidae; these are predatory toward other worms, sedentary inverts (like small clams, foraminifera, etc.), possibly pods, etc. - These shouldn't be a threat to anything large (like fish and inverts we put in our tanks) except for possibly bivalves (like clams).

-Microphthalmidae; there doesn't seem to be much (or any) info on their feeding.

-Pilargidae; there also doesn't seem to be much (or any) info on their feeding.


The most I feel confident in saying is that it's most likely from the taxonomic suborder, Nereidiformia. Also, if you haven't seen any problems in your tank that a predatory worm may have caused, then the worm is most likely harmless/beneficial for your tank.

With regards to the swimming motion, some species of polychaete do swim regularly, and many species swim as epitokes (the reproductive stage of polychaetes).

Very detailed thanks!

I haven’t seen issues but tanks little over month old so not much in there now. I disposed of him and have moved on! Thanks for the replies.