The 6th Tirthankar is Padmaprabha (Padmaprabhu).

• Name and symbol: Padmaprabha means “bright like a red lotus,” and his emblem is the red lotus.
• Birth and parents: Born in Kaushambi. In Śvetāmbara texts his father is King Dhara; in Digambara texts his father is Dharana, and his mother is Queen Susima.
• Path and Moksha: He quickly attained Kevala Jnana after a short ascetic period and ultimately Moksha occurred at Sammed Shikhar.
• Traditions: There are small differences between Digambara and Śvetāmbara accounts on some details, but Padmaprabha is acknowledged as the 6th Tirthankar in both traditions.

You can read more here and also see the general Tirthankar symbols and notes here