Ralph had a rivaly with his next door neighbor Emily, as they caught the same Pokémon. When they caught the Nidoran, they split them, even if they were in love. After their Nidoran were captured by Team Rocket, they set aside their differences and worked together.
Tony (on the right) belongs to Ralph. He fell in love with Maria, but due to Ralph's and Emily's arguing, he was split from her, but continued to see her. When Tony and Maria defeated Team Rocket, Tony evolved into a Nidorino.