In the Amazonian river tributaries in Ecuador, roughly 1000 of the 2500 species of fish can be found. Several examples include: the eel, with its 500 volt shock; the piranha, where a school can devour a cow in a few minutes; the stingray, which can deliver a painful poison to someone who unwittingly steps on it near a shoreline; and the little candiru fish, which can swim up a urethra and lodge itself there. Despite these awful sounding creatures, tourists are rarely affected, and may swim in the rivers safely. Just shuffle your feet when entering the water to scare the stingrays, don't have open wounds or blood to attract the piranhas, and wear a bathing suit to keep out the candiru!