Did This Tiny Fish Really Swim Up a Man’s Urethra? | Smartest Year Ever (June 17, 2025)

It’s Weird Animals Week on Smartest Year Ever—and today, Gordy investigates one of the most infamous creatures in the Amazon: the candiru, also known as the vampire fish.

This needle-thin parasite has a reputation that’s spread far beyond the rainforest—thanks to a viral legend that it swam into a man’s urethra. But how much of that is true? And how did this obscure fish become one of the most feared animals in the world, despite being only a few inches long?

In this episode, Gordy digs into the science, the myth, and the real biology of a translucent fish that feeds on blood, lurks in murky waters, and somehow still manages to be one of the least understood creatures on Earth.

🦇 Yesterday we talked about vampire bats. 🩸 Today, it’s vampire fish. Tomorrow? You’ll just have to wait and see.

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Sources:

• Spotte, S. (2002). Candiru: Life and Legend of the Bloodsucking Catfishes. Creative Arts Book Company.
  

• de Carvalho, M. R., et al. (2013). The case of the alleged candiru invasion of the human urethra in Brazil. Journal of Fish Biology, 82(1), 22–31. https://doi.org/10.1111/jfb.12029
  

• Shepard, G. H. (2004). A sensory ecology perspective on the Candiru. Amazonian Ethnobiology, 9(3), 305–312.
  

• French, K. (2011). The fish that isn’t: myths and misrepresentations of the candiru. Skeptic Magazine, 17(1), 38–43.
  

#AnimalFacts #CandiruFish #VampireFish #Candiru #WeirdAnimals #biologyfacts #wildnature #DailyFacts #DidYouKnow

Music thanks to Zapsplat.