Fiona Phish is a fish that's have seen The Birthday Bird ever since she was born. When Thidwick the Moose finds her she greets him with a big happy "Birthday Bird, how good to see you again, Darling." She even mentions seeing back in the day the Birthday Bird do the famous Birthday Swan Dive. A one and a half ganier quadruple back flip in a tuck position with a double somersault blidfolded. One thing that's pretty neat about this fish is she has some kinda of one wheeled vehicle that helps carry her on the trip to Katroo.

She was featured in the Wubbulous World of Dr. Seuss episode "The Birthday Moose".