Some hitchhikers on fresh LR.

[Dutch_Mill]

Bought about 50kg of fresh LR (it went straight from the airport to my home) to start up a few coral tanks. Besides the dozens of living crabs and a handfull of living pistol shrimps there were some nasties, just curious about what they are. Obviously bristle worms but not a kind I've ever seen before.

Moves extremely slow, seems like it covers itself in detritus as the other bristle worms could go inside it. Looked pretty disturbing. Still alive and crawling after 24h.

And these ones swam very fast (found a bunch of them). They did not seem to have made it through the night though. As they were all dead.

 

[ISpeakForTheSeas]

So, the little white ones look like it's probably a Nereidid worm, possibly a Nereis sp., but I'm not 100% sure. If they are Nereis sp. worms, then they're most likely omnivorous CUC (they will eat meat, but to my knowledge they don't really go hunting, so they should be harmless).

With the big one, do you have any pictures of it under brighter white light? Because if it weren't for the chaetae (bristles) I can see clearly jutting out from the animal in this pic, I'd guess it's a sea cucumber. The chaetae make it clear it's some kind of polychaete worm though.

 

[Dutch_Mill]

So, the little white ones look like it's probably a Nereidid worm, possibly a Nereis sp., but I'm not 100% sure. If they are Nereis sp. worms, then they're most likely omnivorous CUC (they will eat meat, but to my knowledge they don't really go hunting, so they should be harmless).

With the big one, do you have any pictures of it under brighter white light? Because if it weren't for the chaetae (bristles) I can see clearly jutting out from the animal in this pic, I'd guess it's a sea cucumber. The chaetae make it clear it's some kind of polychaete worm though.

Thanks for the reply! I did find Nereidid Epitokes that look like the ones that are swarming in my tank so I think you nailed that one.

Here are some extra pictures of the other creature.

 

[ISpeakForTheSeas]

Thanks for the reply! I did find Nereidid Epitokes that look like the ones that are swarming in my tank so I think you nailed that one.

Here are some extra pictures of the other creature.

So, the best I can do for this ID is family Aphroditidae (Sea Mice), probably genus Aphrodita. These guys are typically harmless CUC members, but one species, Aphrodita aculeata, is known to prey on small crabs and hermit crabs, and some polychaete worms.

Overall, a neat find with these worms - the white color on the little ones is quite unique and pretty, and sea mice are pretty rare and cool as hitchhikers.

 

[EeyoreIsMySpiritAnimal]

So, the best I can do for this ID is family Aphroditidae (Sea Mice), probably genus Aphrodita. These guys are typically harmless CUC members, but one species, Aphrodita aculeata, is known to prey on small crabs and hermit crabs, and some polychaete worms.

Overall, a neat find with these worms - the white color on the little ones is quite unique and pretty, and sea mice are pretty rare and cool as hitchhikers.

I was going to guess a scale worm... And then I searched for sea mice and discovered they are a type of scale worm!

 

[Dutch_Mill]

So, the best I can do for this ID is family Aphroditidae (Sea Mice), probably genus Aphrodita. These guys are typically harmless CUC members, but one species, Aphrodita aculeata, is known to prey on small crabs and hermit crabs, and some polychaete worms.

Overall, a neat find with these worms - the white color on the little ones is quite unique and pretty, and sea mice are pretty rare and cool as hitchhikers.

Considering this one does not have the colorations of the predator version. I'm inclined to give it a shot to live in one of my tanks. Thanksagain for the help in ID'ing.

I was going to guess a scale worm... And then I searched for sea mice and discovered they are a type of scale worm!

Turns out some scale worms can be very neat looking. Makes the one I got look dull.

 

[EeyoreIsMySpiritAnimal]

Turns out some scale worms can be very neat looking. Makes the one I got look dull.

But yours is a sea mouse!! Only thing better is a sea bunny, lol!

 

[Syntax1235]

What about the worm on the bottom right of the first pick? Kind of looks like a red wiggler…. I too got a few in some live rock, put them in my sump.

 

[ISpeakForTheSeas]

What about the worm on the bottom right of the first pick? Kind of looks like a red wiggler…. I too got a few in some live rock, put them in my sump.

I'm not sure - more pics may help, but I struggle with ID'ing smooth worms (there are a lot of options, and I'm not as good at finding the differences between them as I am with polychaetes).