Ferb Fletcher

Ferb is Phineas's stepbrother and is around 10 years old.

Trivia

 * Ferb always has his last sentence at the end and Phineas always responds to Linda.
 * Ferb says to Phineas in the Carwash episode - "You're not very street." AND the BEST bit is that they are ON THE STREET when he says it.
 * It has been hinted by the creators that Ferb's real name might possibly be Frank.