100% flurocarbon line is almost invisable(same light-index as water) under water. It's also thinner in diameter than mono but stronger.
I've been using Seaguar's Carbon Pro f/c line for about 5 years now and it's helped me land quite a few 3-6 lb Bass from ponds bot no double-digit hookups yet;( . Seaguar perfected f/c line for casting and is the largest manufacturer in the world.