Re: Effective small pond fishing
A proper carp rod one of those things you'd want to ask others about, and there will be tons of threads on it on this board. I'm not yet a carp fisherman; one of my plans for the summer is catching one on the fly.
I would think a 5 or 6 weight would be ok for bass and koi, unless one of them was truly behemoth. The sites I've consulted lead me to put 6 weights at a minimum for actual carp. I have twice had carp foul-hooked on a six weight. and it was all I could handle. FWIW, I lost both fish. One was nearly at the end of my backing and I had to try to force him in. (snapped leader). The other I overhorsed stupidly and broke off.
Slow action 8 weights are traditional for largemouths for throwing bigger flies and those big deer hair poppers.