Hi everyone,
it seems to me that there is a little bit of a confusion about the different carp species.
The bighead carp (Hypophthalmichthys nobilis) is the one we are talking about here. This species feeds on microscopic organisms called plankton and besides that it can cause serious problem in the ecosystem it is almost impossible to catch, because of it's feeding habit. It filters the food out of the water, don't actually pick up the bait only by chance.
The grass carp (Ctenopharyngodon idella) looks completely different and behaves completely different.
It eats macroscopic plants (weed) and it can be properly caught pretty muck with the same method as the common carp (Cyprinus carpio). However it is really fun to catch (can grow up to 100lb) it can be just as much of a problem for the ecosystem as any other introduced species.