Western Mosquitofish (Gambusia affinis)

Description: 

The Western Mosquitofish is widespread across Gulf Coast drainages from Mexico to Alabama, including the Mississippi River Drainage north to Illinois. They have been widely introduced worldwide, causing the loss of many native fish species. Western Mosquitofish live in slow water in pools, springs, lakes, and backwaters of streams. They have internal fertilization and give birth to live young.