Name of television movie with evil little girl?(Lifetime/LMN?)

I remember watching a movie when I was younger on tv, probably on the LMN or Lifetime channel. It was about a woman who starts seeing a man who has a daughter. I believe the woman has a daughter as well, and I believe the man’s wife is dead. His daughter is troubled, and I’m pretty sure at one point it mentions how she put her fish in her hamster enclosure, and put the hamster in the fish tank, this killing them. By the end of the movie the father realizes the daughter is evil and him and his girlfriend stop her from killing the other little girl. I can’t remember much else from the movie, but have had no luck when searching based off the detail I do have. Please HELP!!