In common with most domesticated livebearers, the Swordtail’s color and pattern are very different from those of the wild type. Many of these fish have a hybrid ancestry, thanks to earlier crossings both with other types of swordtail and also with platies.
The Platy has a broad body and naturally rounded fins. Spotted patterning on the caudal peduncle and dorsal fin is common in the wild, and it has been maintained in a number of domestic strains.
Platies and swordtails are almost as fecund as guppies. As in the guppy, a female can produce several broods from a single impregnation, and again, like the guppy, they have been manipulated by commercial breeders to produce variations in colour and finnage.
Some of you may be tempted to keep Cyprinus carpio (Koi Carp) in an aquarium and we would like to advise against this. Koi are potentially large fishes best housed in large purpose-built ponds with powerful filtration systems.
