Summer in South Texas is one of the best times of the year to be outside along the San Antonio River. On some days, though, if the heat doesn’t keep you inside, the mosquitoes will. Luckily, the San Antonio River Watershed is home to a native fish that helps us with those pesky insects. The Western Mosquitofish (Gambusia affinis) is a small (1 to 2 inch) fish that lives in ponds, lakes, creeks and rivers. This fish, along with its close cousin, the more localized Largespring Gambusia (Gambusia geiseri), eats mosquitoes. While these fish might be considered pests in some parts of the country where they have been introduced, they are native to our watershed and therefore provide a natural form of pest control. Incredibly common and numerous, these hardy fish are not hard to find.