[header] How to breed livebearing tropical fish [title] Select the species you would like to breed. [step] Several varieties of livebearers are available from most pet stores, including guppies, platies, mollies, swordtails, and endlers. All of these have similar needs. 
Whichever variety you select, ask for a 50/50 mix of males and females. [substeps] Livebearers will do well in a standard 20-30 gallon tank setup.