Possible Clues:

• Female in river swimming backwards can be rather delicate
• Mischievous and somewhat self-involved
• Like a Keebler spokesman
• Dainty morsel of mackerel, finely sliced
• Impish fellow going into the river backwards
• Small force blocking river in retreat
• Like storied North Pole workers
• Like a mischievous fairy
• The sprightly bit of the fish at the bottom
• Initially every little fairy is noticeably puckish