Basically, a livebearer is a fish that gives birth to live young after internal fertilization.  This means that the males have a modified anal fin to accomplish this. Depending on the species, these have different names (e.g. gonopodium or andropodium).

Fish I currently keep:

Ameca splendens
Xiphophorus evelynae
Poecilia latipinna (Sailfin mollies)
Heterandria formosa (lesser killifish)

Formerly kept:

Characodon lateralis 'Abraham Gonzales'
Dermogenys ebrardtii (Ebrart's halfbeak)
Gambusia marshi
Skiffia lermae
Limia rivasi Poecilia chica (Dwarf mollies)
Skiffia multipunctata
Xenotoca variata
Xiphophorus multilineatus (Striped swordtail)
Xiphophorus couchianus
Xiphophorus variatus (variatus platy)
Xiphophorus netzahualcoyotl (Neza Sword)
Xiphophorus helleri (Swordtail)
Xiphophorus montezumae
Xenoophorus captivus Poecilia reticulata (guppy)
Brachyrhaphis holdridgei 'Caño Palma'    Xiphophorus maculatus (platy)

Last updated Oct. 25/16