Trout, who didn't turn 24 until Aug. 7, has 138 career home runs, the most by a center fielder through his age-23 season.
Albert Pujols followed Trout with a laser well over the left-field scoreboard, giving the Angels an early 3-0 lead and marking the fourth time they've hit back-to-back homers this season. Pujols' homer was his 36th of the season, his 50th against the Astros and the 556th of his career, passing Manny Ramirez for sole possession of 14th on the all-time list.