In Adopt Me!, pets go through different stages of growth, from Newborn to Full Grown. Once a player has four fully grown pets of the same type, they can combine them to create a Neon Pet, which goes through a different set of stages. The Neon Pet stages are:

• Reborn
• Twinkle
• Sparkle
• Flare
• Sunshine
• Luminous
• Mega-Neon (Full Grown)

The number of tasks required to age up a pet varies depending on its rarity. For example, a Legendary pet requires 15 tasks to reach Newborn, 26 tasks to reach Junior, 43 tasks to reach Pre-Teen, 72 tasks to reach Teen, 119 tasks to reach Post-Teen, and 155 tasks to reach Full Grown.