What in the world is this thing?

[Hitman]

So out of no where this flat leather looking thing comes out of a hole in my rock. Using the red light I was able to see it, as soon as I turned a light on in the room it went back into the hole. While watching it with the Red light it seemed to move like a snail. What was out of the hole was about 2”x3” and still coming out of the hole till I turned the light on in the room and it then bolted back in the hole. It’s kinda cool in a creepy way but I just can’t figure out what it is.
Background on the rock. It came from my local coral shop that had sharks, stingrays, and several other exotic saltwater critters it that display tank. It’s about a 12”x18” rock that my BlackWidow Anemone lives on.

 

[Hitman]

2 more pictures

 

[kamike91]

To me it looks like a type of polyclad flatworm. They are very photosensitive, but dont react much to red light, and come out only when its dark. If you can, take out that rock and kill it, because they reproduce by budding other pieces of itself off or laying eggs. If you try to get it out with a tweezer you can rip a small shred off and just end up making more. Also just like many flatworms.. when they die I think they release toxins.

 

[Hitman]

They get that big? This thing is the size of my palm if not bigger.

 

[kamike91]

Yeah they get big. I had one that was about five inches. And they are a nightmare to catch because they blend so well and fit into the smallest crevices and are so slimy and fast. Since you can see it now I'd catch it and prevent a headache.

 

[Hitman]

It has not came out since I turn on the light. Looks like I need to order a lot of coral revive as when I looked them up it looks just like it and they say once they get this big coral revive is the only known killer. Thank you sir!

 

[JaimeAdams]

Yes that is an accurate identification. Yes they get that big. I have seen them a number of times. They will eat your snails. I would start breaking down the tank and find that sucker and remove it.

 

[Dsnakes]

If you happen to catch it, let @Shadowbass know

 

[Hitman]

;Sorry Of course the firt pest has to be something like this. Well I better start making 300 gallons of water before I start breaking it
down. I’m officially going to cry.
Thank you for your help.

 

[Shadowbass]

If you happen to catch it, let @Shadowbass know

Thankyou!

 

[sfin52]

is There anything @Hitman can dip his rocks so he doesn’t have to tear down his tank.

Could he also just make enough water to cover the rocks till he get to the flatworm. Could he chisel the beast out or replace the rock and @Shadowbass gets his flatworm.

Never dealt with these guys. Just trying to think of and easier way.

 

[sfin52]

Polyclad Flatworm (P.mopsus) The Clam Killer
by Guy Walker

© Copyright Marian K. Litvaitis, University of New Hampshire, 2005-2007
Phrikoceros mopsus, live animal




​

Like a creature out of a 1950's science fiction movie it glides across a rocky terrain looking for its next victim to devour. This creature is truly a giant, a behemoth amongst its kind I am speaking of the polyclad flatworm Phrikoceros Mopsus the largest unwanted flatworm we see in the hobby and a known clam predator. In my research I could not find exact size ranges for this species but can say I myself have seen a 6" specimen and have heard reports of larger whether true or not I can not confirm.

The Polyclad Flatworm (P.mopsus) is a successful and stealthy nocturnal hunter believed not only to feed on Tridacna Clams but also small worms, crustaceans and snails making them a most unwanted guest in any reef aquarium. These flatworms hunt using chemo-sensory detectors that can detect and track their prey through the chemical compounds they release into the water column. They can kill and devour a clam over night I know this from first hand experience losing six prized clams before finding the culprits.


10 Clams in my 70g shallow reef

This flatworm can be hard to locate in a reef aquarium by nature they are designed to look like the mantles of clams in my opinion they look very much like the mantle of T. squamosa. They tend to hide in your rock work and unless moving blend in quite well making them very difficult to see. There are some signs though that can suggest you have one or more in your aquarium. Sudden and unexplained Clam death of course tops the list but there is another sign people do not normally think of. I was noticing dead snail shells at an alarming rate and had thought originally a mantis shrimp was the culprit and spent several hours looking for signs to no avail. Only after the clams started dying and I finally found on the shell of the last fatality three Polyclad Flatworms did I make the connection. In retrospect the snail deaths were in fact the first signs of the flatworms.

I have found once you have these guys in your tank the best way to remove is active hunting and or using bait and capture. If you have an unexplained clam fatality quickly remove and examine the remains if there is flesh left on the clam and flatworms are the culprit there is a good chance they could still be there. You can bait these guys using feeder clams in a fish trap checking often late at night this is how I caught the last one in my system. It has been over 2 years since I have seen any signs of Polyclad Flatworms.

I have always examined my clams very closely as well as placing them in my frag systems to observe and quarantine before placing in my tanks. I am not sure how I ended up with four Polyclad Flatworms in my tank I am assuming it was the purchase of live rock from a fellow reefer that explanation makes the most sense. If I ever found any sign of parasites in the past I would try and quarantine and treat according to type of suspected parasite. In worse cases I would freshwater dip I do not like this treatment and find it often speeds up or directly causes the clams death.

In March of 2012 I purchased a Black T. squamosa a clam I had wanted for some time and is a favorite amongst my current collection this purchase was made at a large aquarium expo. Being very crowded and me being in a hurry to see all I could at the show I neglected to examine the clam as well as I should have and upon returning home and closer inspection found a Polyclad Flatworm just below the mantle on the shell. At the time I had no quarantine or frag systems up and running and remembering my losses the year before I was very nervous about removing the flatworm and placing the clam in my display. My fear of contaminating my display and possibly losing other clams as a result pushed me to make a drastic decision. I decided to perform an experiment that had been on my mind for some time but had never tried. Not wanting to risk the death of any of my prized clams. I had decided to dip the clam in the commercial pesticide Bayer Advance complete insect killer that is commonly being used in the hobby for dipping SPS corals, all the while fearing I was going to kill the clam. During the dip the clam opened and expelled the liquid several times as if trying to clear its system of an irritant during this time I feared the dip was harming the clam but now believe it was trying to expel dying lifeforms wriggling around in its system. After 10 minutes I placed the clam in a bucket of clean tank water after a moment it opened fully I had to reach in and touch it so it would close and squirt out water I did this a few times to rinse out the clams system of the dip. I then placed the clam in my display and within seconds it was fully open and seemed very happy. Upon examination of the dip container I found the dead Polyclad Flatworm as well as a bristleworm and various unknown small crustaceans upon examination of the rinse container I found another bristleworm and a few more unknown small crustaceans. A month later I dipped a second Squamosa in the same manner it has been 10 months with no sign of ill affects with both clams growing rather well. Although I believe it to be safe it is not my intention to condone or promote the use of untested commercial pesticides in the aquarium hobby and can not guarantee the safety of anyone's livestock but I do feel it pertinent to share my experience based on the topic at hand.

Clam 10 months after dip in Bayer

Keeping Tridacna Clams can be fun and rewarding but as hobbyist we have an obligation to research and understand how to care for the livestock we plan to purchase. Far to many times have I seen new hobbyist purchasing clams on a whim without fully understanding how to care for them or even knowing if their systems are capable. Knowing how to inspect, recognize and treat common predators and pests is a good start and hopefully sharing my experiences can help someone who is looking to purchase a Clam make a better and more informed decision.

 

[kamike91]

is There anything @Hitman can dip his rocks so he doesn’t have to tear down his tank.

Could he also just make enough water to cover the rocks till he get to the flatworm. Could he chisel the beast out or replace the rock and @Shadowbass gets his flatworm.

Never dealt with these guys. Just trying to think of and easier way.

To get mine out I took my rock out and kept it in a bucket with a pump for days and the flatworm wouldn't come out of the hole. I tried baiting with a snail, dead clam, and poking it out with tweezers. So eventually I nuked the rock with clorox... I don't know if it was the best move. Now I have a dead rock that's now cycling in a bucket lol...

 

[Hitman]

@Shadowbass guess what I caught tonight finally!!!

 

[Hitman]

Oh that’s a 2-3” snail shell it’s covering as well as in the shell eating the snail!

 

[sfin52]

Nice work

 

[Soflow Rubio's Corals]

great work on removal

 

[kamike91]

Wow you must be the polyclad whisperer lol. Good catch!

 

[Hitman]

Spotted it with the red light while it was eating a snail for dinner so I grabbed my long tongs grabbed the shell and flipped it into a cup. I sure hope that is the last of them!!!

 

[sfin52]

Do you have a sump you can drop it in