What is the biggest guppy?

The biggest guppy, typically belonging to the species Poecilia reticulata, can reach lengths of about 2.4 inches (6 centimeters). While most guppies are much smaller, selective breeding has produced larger variants. However, size can vary based on environmental factors, diet, and genetics. In general, male guppies are more colorful and slightly larger than females, but females are usually bulkier.