Betsy bugs or whirlygig beetles are vicious little predators, and are not usually found in large enough numbers to be valuable as food. They will actually attack and consume small minnows and shiners. Their 3/4" long cousins will take out any fry close to an inch long.
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The good news is there is food available for the whirligig beetles. Small fish can probably feed on the same food as the beetles as well as the beetles themselves.
