# Flukes? Flatworms??? advice please



## AsEpSiS (Aug 31, 2012)

I have some red bellied piranhas in a planted 125 gal tank that's been established for about 2 years. I only feed my piranhas frozen/thawed catfish, tilapia and chicken....nothing live from pet stores, wild caught or from bait shops.

Today after I fed them, there was a little piece of fish that remained uneaten. I left it in the tank for about 45min or so just so they could eat it if the felt like it. After noticing that they didn't feel like eating the left over piece, I was just about to pick it out of the tank when I noticed something odd.

It appeared to have about 6-10 flat worm or flukes eating/swarming/crawling all over it. I do have some nuisance snails in the tank, but not too many. I've seen many baby snails before....these don't really look like snails. They seem to move much faster and are flatter in appearance. They appear to have the ability to anchor themselves to prevent them from floating around. Almost like a leech. I just don't know how a leech would be able to get in there and reproduce....This is really odd.

I managed to suction up the piece of fish and suspect in inverts. I'll be taking them to a high end aquarium shop near by for a second opinion tomorrow.

I am a graduated Biology/premed major, and have taken parasitology and many bio courses.....these look like flat worms....although....I could be wrong! lol



Help! Advice!? Comments??


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## Zapins (Jul 28, 2004)

They are probably nematodes or planaria. Both are not parasitic and are harmless.

Take a close up photo if you can.

Parasitic worms would not eat dead fish, they'd be on the live fish and die when the host dies.


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## Fishfur (Oct 17, 2013)

If one end, [ the head end] is slightly triangular, with a pair of spots that might be eyes, they're planaria. They can come in with plants, even just in the water with fish or plants, but they're basically harmless. They're not popular with shrimp keepers, having a rep for eating baby shrimp. I'm not all sure the small North American species actually do eat shrimp, but larger fish can and do eat them. I don't know if Piranhas eat from the bottom but if not, perhaps that is why some have survived.

If you don't like them being there, there are some meds, dog wormers I believe, that will kill them, and some types of simple traps that use bait similar to the food you found them on.


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## Zapins (Jul 28, 2004)

Fenbendazole (Panacur) is what you are thinking of Fishfur. Dosage is 1/10th of 1 gram per 10G of water. Kills hydras as well, but not snails fish or shrimp. Just be sure to do a large water change (several) after 2-3 days of treatment or you will start killing fish. I killed some pygmy sunfish because I didn't change the water after using it.

I wouldn't worry about them. Aquariums aren't sterile and trying to make them sterile isn't going to work. Many people new to the hobby go through a phase of "if it wiggles or crawls I don't want it in my tank." But they all come around in the end


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## Fishfur (Oct 17, 2013)

Too true Zapins. I tend to try to culture most of the little things I find wriggling or jumping around for fish food, or simple curiosity. But planaria seem to have acquired a terrible rep, which I don't think they really deserve, at least not the North American species.

There is an Asian species that's truly enormous, which, I have little doubt, could eat a little shrimp.. the big Asian planaria I saw were over an inch in length, 1/4" width. I doubt anyone would tolerate them in a tank just on looks alone.


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## Zapins (Jul 28, 2004)

Well that's the thing about planaria their mouth parts are on the side of their body about half way down not in their heads. It is very weird.

I also don't believe the tales of shrimps being eaten by them alive. I've seen planaria in my tanks wiggling over and inside a dead shrimp in my tank, but never a live one. They are detritus eaters and don't have sharp jaws or anything they could really use to damage a live shrimp. I personally believe that people tend to see dead shrimps and planaria on them and assume the planaria killed them. Which is clearly flawed logic.


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## Fishfur (Oct 17, 2013)

Much my thinking too, where planaria are concerned. Thanks to the way they eat, any healthy beastie is simply going to crawl away from under them, not sit there and allow itself to be digested slowly.


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