Related Clues:

• Relative extent as of laces
• Ratio of, say, map to reality
• An ordered series of units for measurement purposes
• Thin projection for fish to steer itself
• A fish uses it to steer itself
• Climb, or series of notes in music
• Plate on a fish
• Series of notes in an octave
• Doh, ray, me
• Swimmer's flipper
• Not even half a pint of fish - enough to make you sick in the end
• Measure for breath?
• A measure of 6 down?
• C of this for the fish for those who are late
• 11 down has it's forte in it