The word "guppie" is usually used to refer to a small, brightly colored freshwater fish commonly kept in home aquariums. Some synonyms for this word include "mosquito fish", "millions fish" and "endler's livebearer". These synonyms usually describe different species within the same family of fish, which includes over 300 different types. While they may vary in terms of appearance and behavior, the common characteristics of guppies and their synonyms include their vibrant colors, small size, and ease of care. Whether you call them guppies, mosquito fish or millions fish, these tiny swimmers are always a popular choice for hobbyist fish keepers.