Grass Carp are a fish that many people have heard about, but don’t know if they are a good fit for their pond. Grass Carp can be a desirable fish to stock in the right situations but the question is; how do you know if Grass Carp are right for you?
In aging ponds, shallow water can become problematic because it is the perfect environment for aquatic vegetation - which can easily grow out of control. If your lake is susceptible these vegetation issues, Grass Carp may be a relatively inexpensive and effective biological solution to your weed problem.
Grass Carp feed on some types of submerged vegetation, and can eat their body weight in aquatic plants every day. And in Texas waters, Grass Carp can live 10 years or longer, consuming a great deal of vegetation during their lifetime. They grow rapidly, often exceeding 60 pounds, and, the larger the Grass Carp grow, the more effective they become at controlling vegetation. Right until they reach about the age of 7, when, due to a decreased metabolism, they start consuming less.
In Texas, there are parameters involved in obtaining Grass Carp. These fish are considered an invasive species, and are illegal to have without a permit. The permit can be obtained through the Texas Parks and Wildlife Department with a quick assessment of your lake. This process went completely online near the end of 2020 and the can take 4 to 6 weeks to complete - so you may want to visit the TPWD website late in January to make sure you have your permit for the coming summer. Grass Carp must be triploid (or sterile) to be legal for purchase as well. We know what your thinking, “if the fish must be sterile, why do I need a permit?” These fish are permitted so that TPWD can keep track of the location and number of grass carp in the environment.
Impoundments on permanently flowing creeks, or those that overflow frequently, should not be stocked with triploid grass carp unless they can be effectively screened. This means using a minimum of a 2” sq. mesh material over pipe or earthen spillways. Preventing escape helps protect beneficial aquatic vegetation in our public waters. Although triploid grass carp cannot reproduce, they can live for years, potentially migrate to sensitive areas, and consume a great deal of vegetation.
In the right ponds, Grass Carp are a cost efficient tool to managing your pond, and can really improve the quality of fishing. However, it is important to know how many you need, and if the vegetation is correct for stocking Grass Carp. Bushy pondweed, American pondweed, and hydrilla are preferred foods. Grass carp are not effective for bulrush, filamentous algae (pond scum or moss), water primrose, coontail, Eurasian milfoil, or cattails.
Send pictures of your lake, and what type of vegetation problems you are having to firstname.lastname@example.org and we can help you get the necessary solution to your problem, grass carp or otherwise.
Brad Metzler, President
Editor's Note: Originally published January, 2016, this blog was updated in January 2021 for freshness, accuracy and comprehensiveness.