Image for Hanging on

Hanging on

Duration: 01:35

The candiru is a parasite of fish gills and a catfish has nowhere to hide. A trail of urea and ammonia streams from its gills giving signals to the candiru, which simply swims in circles until it picks up the scent. The signal becomes stronger as is gets closer to the catfish and it slips inside the gills unnoticed. Spines in the candiru's head stick into the fish, securing it while it sucks blood from the gills. Humans urinating in the water send the same cues of current and urea and a candiru can end up in the wrong host, causing great pain to the person concerned.

Available since: Thu 4 Oct 2012


Ciaran Mcmenamin
Camera Operator
Rod Clarke
Camera Operator
Mark Payne-Gill
Executive Producer
Keith Scholey
Mark Brownlow

This clip is from

Weird Nature Puzzling Partners

5/6 Series exploring strange animal behaviour focuses on unusual partnerships.

First broadcast: 18 Apr 2002

Image for Puzzling Partners Not currently available on BBC iPlayer

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