[ ABOUT PHINEAS FLYNN ]
Name: FLYNN, Phineas
Age: Less than 15, approximately 11 or 12 years old
Height: Relatively the same as Isabella's
Build: Slender, with a distinct triangle-shaped head
Hair Color: Red
Eye Color: Blue
Hometown: Danville, The Tri-State Area, USA
Parents: Linda Flynn, Lawrence Fletcher (stepfather)
Siblings: Candace Flynn (older sister), Ferb Fletcher (older stepbrother)
Love Interest: Isabella Garcia-Shapiro (at least, she is clearly very interested in him)
Pet: Perry (a platypus that "doesn't do much")
Voice Actors: Vincent Martella, Danny Jacob (occasional singing voice), Robert F. Hughes (old man)
Phineas with his family at their Danville home backyard
From left to right: Lawrence Fletcher, Linda Flynn, Candace Flynn, Ferb Fletcher, Phineas Flynn and Perry the Platypus/Agent P
Phineas Flynn is one of the two titular characters in the animated television series Phineas and Ferb, which airs globally on Disney Channel and/or Disney XD. The series was created by Dan Povenmire and Jeff "Swampy" Marsh.
Phineas Flynn is the youngest child of the Flynn-Fletcher family in Danville, USA. He is the son of Linda Flynn and step-son of Lawrence Fletcher. He is one of the three children of the household, with disapproving biological older sister Candace and stepbrother Ferb, from Lawrence's side of the family. He shares a strong bond with the family pet, a platypus named Perry, but remains unaware of his vague double life as a covert secret agent.
Isabella and Phineas
A notable friend of Phineas is Isabella, a girl around his age living across the street from his current place of residence. His relationship with her as a friend has proven to be very durable, however he is almost completely (if not absolutely) oblivious of her love and admiration for him.
As an incurable optimist, Phineas constantly looks on the brighter side of things. He is also extremely smart, creative, persistent, and able to endeavor in immensely large projects and activities with the help of his stepbrother. His hospitality is a driving force behind many of his plans. He is very friendly and open-minded, resulting to him having excellent relationships with those not only from his family and neighborhood, but also from other countries, other species and even other dimensions and planets.
Source: The Phineas and Ferb Wiki on Wikia