You can get a Gozarutchi if you are a bit neglectful about taking care of it. Meaning, letting it drop a few hunger or happy hearts and not cleaning up its poo right away.
i can be a gozarutchi with high weight it can also be it with small weight just be sure to neglect it if u want those good ones be sure to look at it every 5 minutes!! thats y i pause it when i got to school