If you ask someone the question "Where do baby fish come from?" they usually say "from eggs", and for most fish they are correct. Well, strictly speaking they are always correct, all animals come from eggs, but some groups 'lay' the eggs which develop and 'hatch' outside of their bodies while others give birth to 'Live' babies.

Most of the 27,300 identified species of fish do indeed 'lay' eggs but there is a significant number, Marine and Freshwater, which give birth to live young.

Of greatest interest to us as aquarists are a group of small community fish which we refer to as the Livebearers. The 'Big Four', Guppies, Platies, Mollies and Swordtails are perhaps the best known of aquarium fish and for most fish keepers, their introduction to fish breeding although they are by no means the only live bearing aquarium fish.

There are in fact more than 30 live bearings species which are suitable for the typical home aquarium but which rarely, if ever, appear in the trade.