Vandellia cirrhosa
Candiru

The Candiru is native to the Amazon and Orinoco river basins in northern South America.

This species lives in freshwater streams. It may bury itself in sandy river or stream bottoms when not feeding (FishBase 2000)

Very small, slender fish, 2.5 cm long, possibly longer, with a width of 3.5mm on average. Scaleless, translucent. Has short, sharp, spines on its gill covers (Britannica.com 1999; FishBase 2000; Magallanes 1996).

Not known to author.

This fish is normally a parasite of other fish. It locates its hosts by following the stream of nitrogenous waste normally excreted from the gills. The Candiru swims up the ammonia gradient, and under the gill covers of the host and extends the spines on its own small gill covers to hold itself in place. It then feeds on the host gill. Unfortunately the Candiru can't distinguish between one nitrogen- emitting opening and another, so it has been known to swim up the urethra of humans and other animals who urinate in the water (Britannica.com 1999; FishBase 2000; Magallanes 1996).

The Candiru enters the gills of various large fish, where it then acts as a parasite by feeding on blood and gill tissue (Britannica.com 1999; FishBase 2000; Magallanes 1996).

None known.

These fish can be dangerous to humans. They have been known (rarely) to enter the urethra of people who urinated in a stream or river. The fish apparently does not leave voluntarily, but instead erects its spines, causing great pain. Surgery has been required to remove them (Magallanes 1996; Mansker 1998; Britannica.com 2000; Fishbase 2000).

The Candiru is the closest thing to vertebrate parasite in humans.

There are several species in this family that have similar biologies (Fishbase 2000).