Floracarbon line/Monofilament?

[Quailtail]

Can someone explain the difference of these two lines, and when to use each?

[deathb4disco]

Two different materials. Mono is nylon. Fluorocarbon is ... fluorocarbon.

Fluoro is denser and sinks faster than mono. It's less visible in water and more abrasion-resistant, which is why it's often used as a leader for braid. Fluoro also has less stretch, so it's more sensitive.

[Royalwapiti]

The mono will stretch more as you go to set the hook. The fluoro will not give and set the hook quicker, possibly jerking it from their mouth. Probably not a factor for crappies but for larger fish this is a factor.