In this relationship, the candiru is a fish that lives in freshwater. Humans use the freshwater to swim in. Humans may urinate in the water. The candiru detects fresh urine and swims up the urethra or anus of the human. In the urinary tract, it spreads spines out and lodges itself in the human. It will then suck on tissue and blood from the urethra from the human over a long period of time. The human is hurt and could die from this, if left untreated over time. What type of interaction is this? *