Body color is dark olive, shading to brownish-yellow on the sides, with a white belly and large, slightly outlined scales.

[5] In the wild, grass carp spawn in fast-moving rivers, and their eggs, which are slightly heavier than water, develop while drifting downstream, kept in suspension by turbulence.

[2][5] They eat up to three times their own body weight daily, and thrive in small lakes and backwaters that provide an abundant supply of vegetation.

In the Northern Hemisphere, countries and territories of introduction include Japan, the Philippines, Malaysia, India, Pakistan, Iran, Israel, the United States, Mexico, Sweden, Denmark, the United Kingdom, France, Germany, the Netherlands, Switzerland, Italy, Poland, the Czech Republic, Slovakia, Romania, Croatia, Slovenia, Serbia, Montenegro, Bosnia and Herzegovina and Macedonia.

Grass carp are known to have spawned and established self-reproducing populations in only six of the many larger Northern Hemisphere rivers into which they have been stocked.

Unlike the other introduced fish brought to New Zealand, the potential value and impact of grass carp was investigated in secure facilities prior to their use in field trials.

[16] In some Asian countries, it is believed that ingestion of raw bile or entire gall bladders of the grass carp may improve visual acuity and health.

[17] Grass carp grow large and are strong fighters when hooked on a line, but because of their vegetarian habits and their wariness, they can be difficult to catch via angling.

Where grass carp populations are maintained through stocking as a biocontrol for noxious weeds, fishermen are typically asked to return any caught to the water alive and unharmed.