White flatworms

florida reef · May 4, 2012

So, I woke up this morning, stumbled to the coffee pot, poured myself a cup of Colombian Roast, then made my way out to my frag set up in the garage to continue my morning routine. I walked up to the 40g breeder, which is my only frag tank as of now, and am delighted to see more copepods...or some kind of pods on my glass. I bend down to take a closer look...then wipe the sleep from my eyes and move in for a closer look...and the with my face smushed against the glass I realize I have what appears to be flat worms. I'm stunned...a string of expletives flow from my mouth and I immediately begin to think of how they could have possibly made into my system. In the middle of my jumbled thoughts I remember that flatworms are supposed to be red or rust colored? So I look again and these flatworms are not red or rust, but they are white. A quick google search gave me some hope. Apparently white flatworms (Amphisolops) are not bad but quite the opposite. They eat red flatworms.

Here are a few pics I snapped of these little rascals a few mins ago:

So, as of right now I don't plan on doing anything because apparently these won't eat coral or mess with anything else besides other flatworms. My corals seem fine and the flatworms in question are only on the glass. If anyone else has encountered these white flatworms please let me know or share your experiences here.

-Logzor · May 4, 2012

Acoel Flatworms, they should be harmless.

revhtree · May 4, 2012

HAHA well that was a surprise!

|sCRIBe| · Nov 2, 2016

This is an old post but found it and glad I did! I noticed the same white flat worms on my glass and freaked out. My corals are doing good so I guess these are ok

klimfish · Dec 13, 2016

I have this same creature in my tank. I too thought they were a pest until I came across this post. I know this thread is old but this was one of the only threads I could find anywhere explaining what these are.

jenreefer · Dec 13, 2016

I have them also, and my research said that they are harmless. I know that most people say they have zero tolerance for any flatworms, but I have not had any issues with them so far. cross fingers.

Any input from those that more know than me would be appreciated.

#reefsquad

saltyfilmfolks · Dec 13, 2016

klimfish said:
I have this same creature in my tank. I too thought they were a pest until I came across this post. I know this thread is old but this was one of the only threads I could find anywhere explaining what these are.

jenreefer said:
I have them also, and my research said that they are harmless. I know that most people say they have zero tolerance for any flatworms, but I have not had any issues with them so far. cross fingers.

Any input from those that more know than me would be appreciated.

#reefsquad

Yup. In large numbers they are bad. I have a feeling some of my tankmates are eating mine.

Lionfish Lair · Dec 13, 2016

The ones in the picture are not the clear/ghost flatworms.

Jason mack · Dec 13, 2016

florida reef said:
So, I woke up this morning, stumbled to the coffee pot, poured myself a cup of Colombian Roast, then made my way out to my frag set up in the garage to continue my morning routine. I walked up to the 40g breeder, which is my only frag tank as of now, and am delighted to see more copepods...or some kind of pods on my glass. I bend down to take a closer look...then wipe the sleep from my eyes and move in for a closer look...and the with my face smushed against the glass I realize I have what appears to be flat worms. I'm stunned...a string of expletives flow from my mouth and I immediately begin to think of how they could have possibly made into my system. In the middle of my jumbled thoughts I remember that flatworms are supposed to be red or rust colored? So I look again and these flatworms are not red or rust, but they are white. A quick google search gave me some hope. Apparently white flatworms (Amphisolops) are not bad but quite the opposite. They eat red flatworms.

Here are a few pics I snapped of these little rascals a few mins ago:

So, as of right now I don't plan on doing anything because apparently these won't eat coral or mess with anything else besides other flatworms. My corals seem fine and the flatworms in question are only on the glass. If anyone else has encountered these white flatworms please let me know or share your experiences here.

Thanks now I know what I have in my tank .. I had been wondering for a couple of days now .. I have some that look like little snails or so

klimfish · Dec 13, 2016

Lionfish Lair said:
The ones in the picture are not the clear/ghost flatworms.

What are they then?

Lionfish Lair · Dec 13, 2016

They're just "regular" flatworms.

klimfish · Dec 13, 2016

Lionfish Lair said:
They're just "regular" flatworms.

So if they're "regular" flatworms, should people be worried about seeing them on their glass?

Lionfish Lair · Dec 13, 2016

I personally don't think they're a problem. If people stuck a baster down in their sand and threw the water under a microscope, you'd be surprised the number of tiny little flatworms that are running around in there. They are a very basic primitive natural building block of our little ecosystems.

klimfish · Dec 13, 2016

Good to know. Thanks for your input!

larisa Raykh · Nov 10, 2018

florida reef said:
So, I woke up this morning, stumbled to the coffee pot, poured myself a cup of Colombian Roast, then made my way out to my frag set up in the garage to continue my morning routine. I walked up to the 40g breeder, which is my only frag tank as of now, and am delighted to see more copepods...or some kind of pods on my glass. I bend down to take a closer look...then wipe the sleep from my eyes and move in for a closer look...and the with my face smushed against the glass I realize I have what appears to be flat worms. I'm stunned...a string of expletives flow from my mouth and I immediately begin to think of how they could have possibly made into my system. In the middle of my jumbled thoughts I remember that flatworms are supposed to be red or rust colored? So I look again and these flatworms are not red or rust, but they are white. A quick google search gave me some hope. Apparently white flatworms (Amphisolops) are not bad but quite the opposite. They eat red flatworms.

Here are a few pics I snapped of these little rascals a few mins ago:

So, as of right now I don't plan on doing anything because apparently these won't eat coral or mess with anything else besides other flatworms. My corals seem fine and the flatworms in question are only on the glass. If anyone else has encountered these white flatworms please let me know or share your experiences here.

larisa Raykh · Nov 10, 2018

So I am too glad I saw this post even though after a treated my tank with flat worm exit which didnt do anything. So far no losses for me ..wonder if a Mandarin would take care of it . I also stumbled upon a tiny worm that woyld poke its head out of the sand bed. unfortunately I am unable to upload a video, but it was so tiny I doubt anyone would find it on the picture . I'm not sure what to make of it

Cloud · Jun 8, 2020

Thanks for the post as well as photo. This helps me identify the white flatworms on my tank glass.

Kmargold · Jul 13, 2020

Another thanks from me! Helped ID the little critters I was looking at in my own tank

vetteguy53081 · Jul 13, 2020

Acoel flatworm and a nuisance in large numbers. Remedy is to siphon as many as you can and either add wrasse (melanurus or lunare) or treat with flatworm exit. If using exit, siphon up the dead ones daily which may release toxins