The German Yellow Guppy is a variety of the common guppy (Poecilia reticulata) known for its vibrant, almost solid, yellow coloration on its body and fins, creating a cheerful, "sunny" appearance. These peaceful, hardy, and prolific livebearers are easy for beginners to care for, but their males are smaller, more colourful, and develop long, flowing fins, while females are larger and less vibrantly coloured.