Takoyaki in San Gabriel Valley
Foo Foo Tei in Monterey Park has them on the menu.
Indian in San Gabriel also has an octopus ball item on the menu, but dunno if it is traditional takoyaki -- nothing at Indian is traditional.
633 S San Gabriel Blvd, San Gabriel, CA 91776
Foo Foo Tei Noodle House
750 S Atlantic Blvd, Monterey Park, CA 91754