Poeciliid fish, commonly known as livebearers, are a diverse group of freshwater fish that belong to the family Poeciliidae. They are popular aquarium species due to their vibrant colors and ease of care. Some common synonyms for Poeciliid fish include guppies, mollies, swordtails, platies, and endlers. These species have unique characteristics and are highly popular among aquarium hobbyists. For example, guppies are small in size and come in a variety of colors, while mollies are larger and more peaceful. Swordtails, as the name suggests, have a distinct sword-shaped extension on their tail, and platies have a fan-shaped tail. Endlers, on the other hand, are smaller and more active than other Poeciliid species. Overall, Poeciliid fish are a fascinating group of fish with many synonyms that describe their unique features.