Guppies are probably the most well-known aquarium fishes. Many aquarium keepers started with guppies and many very experiences aquarium hobbyist still keep guppies. There are specialist guppy associations, who specialise on breeding of specific strains. However, what do we really know about guppies? This Mini informs you how a guppy aquarium should look like, what water you use for guppies, guppy diseases, behaviour, reproduction and breeding of new varieties, and relatives of guppies in nature.