Yes. Outside their native range, mosquito fish (Gambusia) are widely considered invasive, and the U.S. Geological Survey says they have had the greatest ecological impact of any introduced fish in their family.
The western mosquitofish is native only to the Mississippi River basin, from central Indiana and Illinois south to the Gulf, and Gulf Coast drainages west to Tampico, Mexico. Starting in the early 1900s, it was stocked around the world to control mosquitoes, including Hawaii in 1905 and California in 1922, and it is now established in most states where it was released. Reviews have not found it especially effective at reducing mosquitoes or mosquito-borne disease. Instead, the aggressive fish eat the eggs and young of other fish, shred the fins of larger fish, and compete with native species. It has helped wipe out or reduce endangered fishes in the American West, such as the Sonoran topminnow in Arizona. By eating zooplankton, it can also trigger algae blooms. Cold winters limit its spread in northern states.
Source: USGS Nonindigenous Aquatic Species, Western Mosquitofish (Gambusia affinis) profile
Image: Western mosquitofish, by NOZO, CC BY-SA 3.0, via Wikimedia Commons.