You know what happens when you overfeed goldfish? They grow up to be sharks!
12 seconds sound clip from the Poltergeist (1982) movie soundboard.
You can hear this line at 00:12:53 in the Blu-ray version of the movie.
Quote context
[...]
- Come and get it. Come and get it.
- Honey, you're overfeeding them.
- Tweety Two and Tweety Three want seconds.
- You know what happens when you overfeed goldfish? They grow up to be sharks!
- Mom, there's a big storm headed this way.
- You'll be asleep by the time it gets here, if you hurry. Come on. In you go.
[...]