As bizarre as this sounds, it's Not the first time it's happened.
Under different circumstances, it happened to a South American Man as well.
I was watching an episode of Monster Fish on cable, having several subjects they cover on different episodes.
In one episode, they catch a mammoth redtail catfish. They show how it has these small parasite like fish in it's mouth where they survive by taking small amounts of blood from the catfish.
Before retuning the big cat to the river. They clean him out of the small parasite like fish.
Then the program showed how a human was accidently infested by one these on a different occasion.
A Brazilian Man was standing in the river just a little bit off shore. He got out of a boat to take a "pee". While standing there urinating in the river, The small fish(3-5" in length) jumped up - swam up the mans urine stream and into his penal canal.
He did not know what happened. But after tremendous pain finally went to the hospital. It took a few days travel since he was far from civilization.
In the hospital they showed a scope viewing the fish inside him and how they extracted it! The fish was burrowing it self further and biting on internal flesh. But they got it out and the man made a full recovery.
It was the same kind of fish that used the red tailed cats mouth to host in. Interesting & strange behavior... disgusting.
What a nasty fish!