Caught a polyclad! (edit: not a polyclad? Looks like a giant AEFW.)

[Tired]

Went to go brush my teeth before bed, figured I'd shine a flashlight in my tank on the way and see if there was anything out and about. Lots of amphipods, and a weird splotch on the back wall. My first thought was "slime mold" because I used to have terrariums, but those are terrestrial, and I'm pretty sure they'd die if you so much as mentioned salt near them. Then it started moving. 

I actually managed to catch it there, right on the spot. Slid/chased it up the back wall with a spoon until it got to the top, then quickly peeled it up by hand. 

It's about an inch long. I put it in a cup of tank water, floating in the tank to keep the temperature stable, with half an inch or so of space above the waterline in the cup so it won't get out. 

 

Anybody want this guy? It's a cool animal, I hate to kill it, but I don't know that I have the resources for a separate thing to put it in. I also kinda need my snails, or I'd put it back. 

I'll try shipping 2-3day mail if anyone out of Austin wants him. 

 

Also, are these possible to ID by appearance? I can get a better-lit photo in the morning if it's possible to get them down to species in photos.

[Snow_Phoenix]

47 minutes ago, Tired said:

Went to go brush my teeth before bed, figured I'd shine a flashlight in my tank on the way and see if there was anything out and about. Lots of amphipods, and a weird splotch on the back wall. My first thought was "slime mold" because I used to have terrariums, but those are terrestrial, and I'm pretty sure they'd die if you so much as mentioned salt near them. Then it started moving. 

I actually managed to catch it there, right on the spot. Slid/chased it up the back wall with a spoon until it got to the top, then quickly peeled it up by hand. 

It's about an inch long. I put it in a cup of tank water, floating in the tank to keep the temperature stable, with half an inch or so of space above the waterline in the cup so it won't get out. 

 

Anybody want this guy? It's a cool animal, I hate to kill it, but I don't know that I have the resources for a separate thing to put it in. I also kinda need my snails, or I'd put it back. 

I'll try shipping 2-3day mail if anyone out of Austin wants him. 

 

Also, are these possible to ID by appearance? I can get a better-lit photo in the morning if it's possible to get them down to species in photos.

I'd totally take him - but currently on the opposite side of the world. 😕

 

Hope he finds a good home/pest tank to live in! 🙂 

[Ratvan]

2 hours ago, Snow_Phoenix said:

I'd totally take him - but currently on the opposite side of the world. 😕

 

Hope he finds a good home/pest tank to live in! 🙂 

You and me both

[Tired]

Welp, apparently you can't keep polyclads in floating cups like that. Little blighter got out! He's back in the tank now. I guess he wanted out badly enough to crawl out of water for a short distance. 

 

My snails all currently seem to be alive, though, and this guy wasn't very fast-moving when I was trying to catch him. He sure wasn't moving like the greased lightning I've read these can be. Is there such a thing as a non-snail-eating polyclad? 

[Ratvan]

Aren't they supposed to eat Clams, Worms and Crustaceans as well as Snails? Might have worked through those first in your tank before moving onto snails as a necessity 

[Tired]

Seeing the little reply emoticons. Yeah, that was about my face, too. I'd made sure not to fill the cup all the way, and it had a frag plug in the bottom to keep it stable. It definitely didn't tip. He would have had to stretch across over half an inch of dry cup, squeeze under the lid, and then go down the outside of the cup to get into the tank. But, apparently, they can do that! Good to know, I guess. 

 

If I can get him again, I am a little tempted to start a tiny pest tank. Or- these don't hurt rock flower anemones, I don't think, and I was planning to maybe start a RFA growout tank. Wasn't going to put snails in it because they'd just grab the snails, so maybe he could go in there. It's a bit of a moot point now that I don't have him and am unlikely to see him again, though. Apologies, snails. 

 

I don't seem to be having any bristleworm population issues, my feather worms are still there, and I don't have very many clams. The few I do have aren't the tridacnid bunch, and seem to be alive. He's certainly not doing much to my amphipods, not that he looked like he could move fast enough to get one. I wonder- COULD he be a kind that doesn't chase down prey? He's awful slow. I think a spooked nerite could outpace him.

[Tired]

Gee! I wonder why there's some empty dwarf cerith shells in here now? 

 

Gonna try and spot my nerite so I can get it out before he eats it. Maybe if I leave the tank without snails for a couple weeks I'll be able to bait him out.

[Opotter]

I feel your pain!!!  I had two of them in my Evo before I tore it down for an upgrade.  I didn’t really try to catch them though, it was just the final straw scenario.  I do have to share though.  I took that tank apart rock by rock to save as much life as I could to seed the new tank.  Never came across them.  Even sifted the sand for bristle worms.  Took the tank out in the yard to wash with a hose.. sprayed the hell out of it with cold fresh hose water. Put the tank on porch to go get towels to dry, put the dogs up etc.  Came back out like 30 mins later towels in hand.. and to my horror.. those two ugly worms were hanging out in the back chamber still moving (much more slowly.. but still freaking kicking).  I was floored.. when I finished squealing like the girl I am.

[Tired]

I have a lot of chitons. If I can't catch it out, no real problem- I'm going to be stirring the sandbed a little during water changes anyway, and the chitons should keep the algae down for me. 

 

I'll have to remember to check the back chambers of this now and then. Maybe it's in there. It would certainly be easier to catch out of there than off a rock! Just gotta slide it up the plastic with a spoon again. I personally don't mind the look of them, in fact I think they look cool, but I could see how the size of them would freak some people out.

 

 

 

 

 

[TatorTaco]

I'm near Little Rock and might be interested in it.  He might be a bit too big for my little 4G pest pico. 

[Tired]

I'll definitely let you know if/when I catch him again.

[Tired]

GOT HIM AGAIN. He's smaller than before, but considering he hasn't eaten in over a month, it's not surprising. I've been checking almost every night for him, and I finally spotted him, gliding along the bottom of the glass. He tried to hide under a shell on the sandbed, but I grabbed it up with my tweezers, then grabbed him. Don't think I did him any harm. I assume he can live overnight in this cup. 

 

 

@TatorTaco you still want this guy?

 

(edit: at least, I hope this is the same one. I know flatworms shrink when not fed, so I assume it's the same flatworm. I better not add in new snails and turn out to have another little bastard splotch running around in here.)

[TatorTaco]

I'm not sure.  I think I already have one of these guys in my tank and I'm not sure it could sustain 2 of them.  😞

[Tired]

They don't eat algae and the like. If you have one, it'll eat all your snails, and then you'd have to manually feed it pieces of shrimp and whatnot. 

 

Have your snails been going missing? You could always pull out all your remaining snails and wait. Either it'll get hungry and come out to look for food more often, or you'll be able to bait it out in a couple weeks with an added-back live snail. 

[SeaFurn]

1 hour ago, TatorTaco said:

I'm not sure.  I think I already have one of these guys in my tank and I'm not sure it could sustain 2 of them.  😞

Do it!!

[mcarroll]

On 2/26/2020 at 10:19 PM, Tired said:

He's smaller than before, but considering he hasn't eaten in over a month, it's not surprising.

You had attributed multiple empty snail shells to him though.....it seems contrary now to say it makes sense that he's smaller.

 

Those snails would have been huge meals for such a small critter.

 

It seems like an assumption that he's eating them without knowing the type of flatworm he is.   Sometimes these worms apparently just live in the shells for cover while the animal is still in possession of it:

Quote

Often polyclads are associated with other invertebrates, such as bivalve mollusks, sponges, corals, or ascidians. In such associations, the worms may use the invertebrates as a source of food, or they may find protection from predators inside the structural framework of these "hosts".

 

Do you have hermit crabs in this tank, BTW?

 

Easier said than done of course, but any chance you can ID your flatworm on this site?

 

Flatworms - Marine Species Identification Portal

[Tired]

I do have hermit crabs. I didn't suspect them because they're far too large to fit into a dwarf cerith shell, but I guess they could have decided they'd like some protein. SOMETHING ate my snails, and I removed the last intact one a month ago. That is a lot of snails for this guy to eat, though.

 

My new order of dwarf ceriths came in, and I didn't want this guy to starve, so I put one of the feebler-seeming ceriths in the holding tank with him. He didn't touch it. I may have to have a word with my hermit crabs, and make sure they're getting fed enough. Because I'm now pretty sure this guy isn't eating my snails. So, what DOES he eat? Seems like nothing that my tank has in it, unless this is a different one and he did not, in fact, shrink. 

 

I've been looking online, and I have a question: how big do AEFW get? Nowhere near this size, right? Because he actually looks a whole lot like one of those. He doesn't have any antennae or other little fancy bits. He DOES have a stomach (or, digestive apparatus, not sure if these have stomachs) that's visible from the underside, with nothing visible in it. 

Any idea what this eats? If the answer is "nothing anyone will reasonably give it", I'll just euthanize him to save him the trouble of starving to death.

[mcarroll]

Did you have any luck with that ID site?

 

Any chance you can get an even better photograph of him? Especially a clear shot from the top and a clear shot from the bottom – both close-ups.

 

There are lots of similar flat worms (some only have drawings) and it's a little too hard to make out details on your existing photos.

 

I don't know what confidence level to put on this, but the one yours looks most similar to that I have seen so far is one that's actually an Atlantic species and seems to cohabitate with ascidians.

 

Could explain yours apparently not eating....But again I'm not sure what the confidence level is with this ID.

[Tired]

I'll try for a better shot later tonight, when he's moving around. He's definitely nocturnal, but I think that goes for a lot of these guys. 

 

I have a small sea squirt in here. It looks nothing like this flatworm, though, and I know a lot of flatworms mimic whatever they spend time on.

[mcarroll]

5 hours ago, Tired said:

I'll try for a better shot later tonight, when he's moving around. He's definitely nocturnal, but I think that goes for a lot of these guys. 

 

I have a small sea squirt in here. It looks nothing like this flatworm, though, and I know a lot of flatworms mimic whatever they spend time on.

I've heard a lot of them are actually photo-phobic...you might be able to chase them around with a flashlight. 😉

 

I'm not sure the mimicry is universal either, but I know it;s at least somewhat common.

 

A lot of them seem just to look like they're mimicking a sand bed.

 

Are there corals in the tank, so we at least have an idea that he's also NOT a coral-eater?  (Again, noting the shrinkage over time.)

[Tired]

He doesn't actually seem to mind the light too badly. He moves around a little during the day, he's just far more active at night. He certainly tried to flee when I shined a flashlight on him at night, but I think that may have been due to being disturbed.

 

There are zoanthids, a clove polyp, and some acan lords in the tank. None of the above seem to be missing unexplained parts. I don't have any SPS. 

[TatorTaco]

This has been my experience with my flatworm.  I have zoas, macro algae, and red planaria.  I do occasionally feed the tank a little flake food.  I'm too lazy to look back at my tank, but I reckon I've had my big flatworm a couple months now and he's still rocking and rolling.  

[Tired]

This one was definitely shrinking, and starting to look sort of tattered around the edges. I euthanized it last night to save it the trouble of starving it to death, since I have no idea what it eats but it clearly wasn't getting enough. Tiiiiny drop of clove oil mixed into a cup of water, put whatever you want to euthanize into the cup, and it slows down until it stops. THe clove oil is an anesthetic. No signs of distress from the worm, no darting around trying to escape like if I'd put it in fresh water. Faster than the couple of fish I've had to euthanize- I guess because it can absorb things with its entire body? Whatever the case, it's dead. I don't know if flatworms feel enough to be distressed when starving, but I felt bad just letting it wither away for however long these take to starve, so.