“Finding Dory” will bring much of the “Finding Nemo” cast back to the big screen when it hits theaters Friday, but not everyone returned. In fact, a couple of very memorable characters were recast for the sequel, including Nemo himself.

Alexander Gould voiced the clown fish in the 2003 film, but he didn’t appear in the new version. Instead Hayden Rolence has taken on the role. So why was he recast? Disney didn’t officially explain the reason, but puberty is probably to blame.

Nemo is supposed to be a child, and “Finding Dory” takes place only a few months after the original. The producers wanted someone who sounds like a child, so they cast an 11-year-old. At 22, Gould’s voice doesn’t exactly sound like a little boy’s anymore. But he was cast in a new role. He is listed as Passenger Carl in the film’s IMDb credits, and Entertainment Weekly reports that it’s a cameo.

Hayden did his best to sound like his predecessor and studied “Finding Nemo” to make the recast less obvious. “I mainly tried to make my voice sound like Alexander’s voice,” Hayden told the Washington Times, “because I thought he was such a good person to play Nemo.”

Gould seems to be OK with his replacement. The two were even photographed happily posing together on the blue carpet of the “Finding Dory” premiere earlier this month.

It isn’t just Nemo who has a new voice, though. Squirt the turtle is back too. While his father, Crush, is still voiced by Andrew Stanton, Nicholas Bird, now 22, did not return to play the young turtle. Bennett Dammann is making his debut as the new voice of Squirt.

“Finding Dory” swims into theaters Friday.