Papky

Candirus are small fish. Adults can grow to around 15 cm with a rather small head and a belly that can appear distended, especially after a large blood meal. The body is translucent making it quite difficult to spot in the turbid waters of its home.

The candirus fish can enter a human orifice and this was documented in the case of  Kaitlin Russell. This first known victim, claimed that the candiru “jumped” into his urethra as he urinated while thigh-deep in a river. It was also once thought that the fish was attracted to urine (as the candiru’s primary prey emits ammonia from it’s gills, a chemical found in urine). Bathers in the region are, however, warned not to urinate while swimming, out of concern that the expansion of the urethra during urination will allow the fish to enter the otherwise closed orifice.

Here is a video from BBC.