Are Gerridae harmful to koi fish in a pond?

Gerridae, commonly known as water striders, are generally not harmful to koi fish in a pond. They primarily feed on small insects and organic debris on the water's surface and do not pose a direct threat to larger fish like koi. However, if their population becomes excessively large, they could potentially compete for food resources, but this is unlikely to harm the koi significantly. Overall, their presence is more of a natural part of the pond ecosystem.