The Guppy, Poecilia reticulata, is one of, if not the, most popular aquarium fish. Between the myriad of shapes and colours they come in, their hardy nature, and ease of breeding, guppies have remained a mainstay of the hobby since their introduction. While females may be somewhat bland, males have quite intense colouration and long flowing fins. They make good community fish, generally getting along with any other comparably-sized, peaceful fishes. They are also valued for their use in cycling aquaria; guppies are able to withstand sub-par water conditions quite well, and are a good choice as the first fish for a new aquarium. Guppies are livebearers, meaning they give birth to live young as opposed to laying eggs. If males and females are kept together in aquaria, it is almost certain they will breed without any extra effort on their keeper's part. To avoid females being harassed, it is suggested to keep either only males or 2-3 females per male (or more!).
These are the ever popular Metallic Blue Neon morph, all adult males.