Ritsu's Breloom
Breloom is Ritsu's eighth Pokémon she caught prior and debuted as a Shroomish. He made its debut in Be Calm and Snorlax! and was confirmed male in the same episode.
As a Shroomish
In "What's In a Nickname?", he was officially nicknamed Loomy by Ritsu, and even nicknamed the other Pokemon she has owned.
He was later confirmed male since Ritsu mentioned his gender and referred to him as a guy, confirming its gender to be a male. Its ability Poison Heal activated for the first time after getting hit by Golbat's Toxic who was owned by a Team Flare Grunt. Due to Poison Heal, it healed Loomy instead of hurting him from poison, much to Ritsu's surprise and delight, it defeated the Golbat with a Seed Bomb and Sky Uppercut combination.
Loomy's known moves are: Sky Uppercut, Seed Bomb, Protect, Helping Hand, and his ability is Poison Heal.