pale white drop shaped simple animal

The tank is set up since nearly two months now. The shrimp have been in it for around four weeks. One small algae eating fish and one big and accidentally some small snails are living there too. But this strange alien I cannot connect with any of the other. It is around one cm in length and seems to have some kind of spine and a kind of mouth on the spiky end. I imagine some kind of flat worm. I assume it was hiding in some plant, as we bought them...

The important thing: is it dangerous for humans or the life in the aquarium?

  • I'd get it out of the tank if I were you Commented Mar 6, 2021 at 11:13
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    @animaltrainergirl I got it out the same evening ;) Commented Mar 7, 2021 at 11:46

1 Answer 1


I found it is the German "Kleiner Schneckenegel" (Alboglossiphonia heteroclita, synonym: Glossiphonia heteroclita) which is a kind of leech. They eat snails and other related kind of animals. I found the German Wikipedia page but it seems there is no English source for this on Wikipedia. If someone knows a source, I would be happy to add it.

The small snail leech mainly sucks on snails, including those of the genus Lymnaea, which are often suckled by several leeches at the same time. Smaller prey such as worms and insect larvae are also sucked out, usually completely. Therefore, the small snail leech can be classified as a predator.

Snail leeches crawl forward on the ground. They are often very agile and lively.

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    gbif.org/species/2307918 Commented Nov 15, 2020 at 9:52
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    Thank you for the site @trondhansen :) Sadly this site does not allow to read it, without accepting all cookies :( Maybe you have another one? Commented Nov 15, 2020 at 15:50
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    there is this page about leeches en.wikipedia.org/wiki/Leech it is about leeches in general but it might be helpful if you want to learn more about them.most freshwater leeches eat the blood from snails and mussels but some types can suck blood from the gills of fish sometimes resulting in secondary infections or anemia. Commented Nov 15, 2020 at 16:34

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