Candiru - the Toothpick Fish

Candiru (English and Portuguese) or candirú (Spanish), also known as canero or toothpick fish, are parasitic freshwater catfish of a number of genera in the family Trichomycteridae. They are found in the Amazon River and have a reputation among the natives as the most feared fish in its waters, even over piranha.^[1] They are eel-shaped and translucent, making them almost impossible to see in the water. Some species have been known to grow to a size of 6 inches (~15 cm) in length.

This fish is also known to attack humans and animals and swim into an orifice (the urethra, anus, or vagina).^[4] Because of spines protruding from the fish, it is almost impossible to remove except through surgery.^[8] Though there have been documented candiru attacks on humans,^[9] there is no evidence the fish can survive once inside a human. The danger for the person lies more in the infection and shock that results from having the organism lodged in sensitive tissues for an extended period of time than from physical damage done by the actual fish itself.

The fish locates its human targets when people urinate near the fish. A well-circulated myth is that the candiru is capable of swimming up the stream of urine in mid-air to a victim standing on shore or a boat, although this assertion is false. Nonetheless, there was a case in which the victim claimed that the fish jumped while he was urinating thigh deep.^[9] They are also probably not attracted to pure urine.^[4] It is believed that they are able to enter a human urethra only when it is expanded during urination.^[9]

A traditional cure involves the use of two plants, the jagua or jenipapo plant (Genipa americana) and the Buitach apple which are inserted (or their extract in the case of tight spaces) into the affected area. It is thought that these two plants together will kill and then dissolve the fish.^[10]

It has also been mentioned in the films Anaconda, The Rundown, Medicine Man, Sniper and the RiffTrax version of Predator.

Here is some info and terrifying photos of candiru removal: LINK

Text from wikipedia.