Fish breeders have developed many forms of long-fin swordtails, as well as platies and guppies. By making use of the fact that these fish are prolific and produce mutations quite often, expert aquarists have managed to selectively breed for the longer fins. The first ones were called the Simpson hifin swordtail. There have been many others since these were introduced many years ago. Aquaculturists, particularly in Singapore and Hong Kong, continually develop new strains of long-fin swordtails and platies.