RIO's Tropical OutBound Short is a great line for mahi-mahi fishing. This line will let you quickly deliver a long cast. Use the floating version for poppers and the intermediate for bait fish patterns. RIO's Coastal QuickShooter XP will also fill the bill. if you prefer a line with a less aggressive taper, try the General Purpose, Tropical Floater or Intermediate. Spool these up on a Sage 6210 reel and a sage salt, X or Method rod, and you've got the tool to get it done. Nine to 10 foot saltwater tapered leader has a medium stiff butt section that will let you turn over unruly flies like Crease flies. it is a good idea to add a foot or so of RIO's Fluoroflex Saltwater tippet in 25 or 30 pound test. this extra bite tippet will protect your leader from the mahi-mahi's teeth. Their teeth are not that big but will wreck your tippet on a prolonged fight.