Coltrane

Coltrane is a friend of Jeremy Johnson in Phineas and Ferb. He is the bassist in his band, Jeremy and the Incidentals, and a love interest in Stacy Hirano. He, along with Jeremy and the band's unnamed drummer, performed at the Summer Festival, during which they were briefly transformed into a punk rock version of themselves by Dr. Doofenshmirtz's Ugly-inator. ("The Best Lazy Day Ever").

Coltrane was later seen watching Jeremy's TV commercial with him; he then changed the channel to see Candace on Phineas and Ferb's game show ("Let's Take a Quiz").

Coltrane is also an instructor at the "Summer Rocks!", a summer course that Baljeet was enrolled in ("The Baljeatles").

Stacy Hirano
Coltrane appears to have a love interest for Stacy. While performing Do Nothing Day, they can be seen smiling at each other similar to Candace and Jeremy's way of smiling at each other during the song ("The Best Lazy Day Ever").

The two later formally introduced themselves to each othеr during the "Summer Rocks!" concert. They immediately show mutual attraction to each other, including dancing with each other during "Gimme a Grade" and holding hands afterwards. He also said he would teach her to play bass ("The Baljeatles").

Jeremy Johnson
He is great friends with Jeremy Johnson. He may be like what Stacy is to Candace, a best friend. He is seen watching TV with Jeremy and talking with Jeremy during the "Summer rocks!" concert. He is also seen at Jeremy's party ("Let's Take a Quiz", "The Baljeatles", "De Plane! De Plane!).

Candace Flynn
Not much is known about Candace's and Coltrane's relationship, who are only shown as apparent friends in the few episodes he is featured.

Background information

 * In "The Best Lazy Day Ever" and "Let's Take a Quiz", Coltrane wore a red hat, t-shirt and shorts. His character layout and appearance was changed in "The Baljeatles" so that he would look more like his voice actor, Corbin Bleu. However, in "Make Play" and "Candace Gets Busted", he switches back to his original outfit.

Appearances

 * "The Best Lazy Day Ever"
 * "De Plane! De Plane!" (Cameo)
 * "Let's Take a Quiz" (Cameo)
 * "The Baljeatles"
 * "Phineas and Ferb Summer Belongs to You!" (Cameo)
 * "Make Play" (Cameo)
 * "Candace Gets Busted"
 * "Rollercoaster: The Musical!"