A dragon's spell-like abilities depend on its age and variety. It gains the abilities indicated for its age plus all previous ones. Its age category or its sorcerer caster level, whichever is higher, is the caster level for these abilities. All spell-like abilities are usable once per day unless otherwise noted.
The save DC is 10 + dragon's CHA modifier + spell level.
Based on the entry in Dungeons & Dragons Monster Manual 3.5