Do not be fooled! This is not the 1978 movie about carnivorous fish!
In this movie, a wildlife photographer (Terry Greene) and her brother (Art Greene) venture into the Amazon on a photography expedition (she got a grant to finance it). Art has no relevant skills, so seems to be just tagging along, drinking, and seducing Venezuelan women on the way. They hired Jim Pendrake to be their local guide, and he seems to know what he's doing.
Along the way, they meet infamous local hunter, Caribe (which is apparently Spanish for "piranha"). Caribe offers to show them a local diamond mine, which gets Art's attention, and Terry agrees to go along to take pictures. Caribe starts showing more interest in Terry.
They all proceed to a small native village deeper in the Amazon where Caribe has a private lodge. It's here that the vibes start to get really bad, and Art decides they should get out of there. Too late, though. Terry gets attacked, and when Art seeks revenge, Caribe kills him. Jim tries to escape with Terry, but Caribe has disabled the jeep that brought them.
The end was predictable enough, but it requires more context for it to make sense, so I'll force you to watch the movie if you want to find out.
I'd say this probably rates two slimes.