The problem with Asian Carp is that they present a threat to currently existing ecosystems in the United States mainly by out-competing native fish in food and other resources, quickly dominating certain bodies of water, and potentially endangering certain native species in their natural environment.

As most native fish in the United States, such as bass and crappie, feed on plankton during their larval and juvenile life stages, they start to prey on other things when they grow up. However, that is not the case with some species of Asian Carp which have to stick with the largely plankton-based diet for their entire lives.

As a consequence of its diet preferences, Asian Carp can impact the stability of the food network heavily. The existence of Asian Carp in large numbers could reduce food sources for larval fish and native planktivorous fish which serve as prey to important predatory sports fish such as walleye and trout. It is reported that the decline of gizzard shad, big-mouthed buffalo, large-mouth bass, crappie, blue gill, and catfish in the Illinois River correlated with the Asian Carp boom. Even though there are predators of Asian Carp such as walleye, eagles, and pelicans. Asian Carp tend to grow too large and too quickly for natural predation to be a significant pressure to hold down their populations.

As a result, almost all major rivers feeding the Mississippi are overwhelmed with Asian Carp, including the Ohio, Missouri, Arkansas, Tennessee Rivers and many other smaller streams and ditches. In some parts of the Illinois River, Asian Carp are reported to account for nearly 90% of the animal mass.

Although the Mississippi watershed is home to more than 99% of the Asian carp in the United States, much more attention and resources have been given to the Great Lakes. Some experts envision that if Asian Carp enter the Great Lakes they would thrive, which might totally change or even devastate the Great Lakes' ecosystem. Other experts counter-argued that the warm-water Asian Carp are unlikely to flourish in the chilly Great Lakes.

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