Your rigs do not need to be complicated for any of these species, they just have to be strong and reliable, afterall you are fishing for some of the biggest freshwater fish in the WORLD!
For the carp and majority of other fish that swim in the lake then we would suggest Korda's Armakord in 85lb or Korda Hooklinks in 65lb. Kryston Ton Up is also a great hooklength.
For the Arapaima we would suggest Catfish Pros's Catlink XT in 120lb.
Put simply, this is the sinking version of our all-conquering Arma-kord leader material. Arma-kord has rightly developed a great reputation for reliability and the addition of this sinking version will simply cement its place at the very top of the tree. Reach for this on demanding waters where snags make a solid snag leader essential.