Is ONE PIECE episode 29 filler?
Canon No, episode 29 of ONE PIECE is canon.
#29
The Conclusion of the Deadly Battle! A Spear of Blind Determination!
決闘の決着！腹にくくった１本の槍！
Aired 21 Jun 2000
Mochibayo compiled this list from MyAnimeList's labels, because MyAnimeList's episode data is not reaching us at the moment.