Controlling pond vegetation with fish

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Radio interview source: Jack Whetstone, Extension aquatic specialist, Clemson University

We have huge grass carp and they were in the pond when we bought our acreage more than 20 years ago. They're ugly, and not too tasty in the frying pan, but useful for weed control. Because we have more than a few carp, we never have vegetation problems in the pond.

Aquatic Specialist Jack Whetstone at Clemson University says grass carp do a great job of controlling certain aquatic weeds.

"Primarily submerged weeds and primarily soft-stemmed submerged weeds," Whetstone says. "They don't work immediately, they do take a period of time, but they actually will control aquatic weeds for multiple years, so they may be fairly expensive up front, but they do control weeds for a period of four or five years, and they can live longer than that."

Be aware of stocking regulations in your state. Some allow grass carp, some don't. Others will only allow a species called "triploid carp" that is sterile and can't reproduce. This species of carp can devour its body weight in vegetation in a single day, and grow to more than 50 pounds.

Grass carp should be stocked at about 15 fish per acre. Those numbers can vary depending on the type of weeds and how much you have.