Swordtails

Photos by Ken Petersen

Swordtails and Platies both belong to the Genus Xiphophorus. and although they are obviously very closely related they do require a slightly different approach to breeding them on purpose.

They come from Mexico to N Central America. The females are much bigger than the males, and they are vegetarian but some live food should be included in their diet. They should be kept at a temp of 75 F to 78 F, any higher than this could affect the fertility of them. They also prefer water with a pH of 7.5 and medium hard. These fish also live well inland away from the sea, they do not benefit by adding salt to their water.

The males do not apreciate the company of other males so you can either kepp one male with a group of females or keep a group of at least 5 males so that any aggression is spread out nd cause little harm.

Being livebearers the females can produce upto 8 broods from a single mating and each brood can vary from 25 fry up to 180, depending on the age, condition and size of the female. In the wild these fish are seasonal breeders, but in the aquarium they breed all year round.

Swordtails are highly cannabalistic on there fry, unlike their close relations the platies which rarely eat there on offspring. To combat this the pregnant female should be placed in a tank by herself with just a sponge filter and lot of plants. For the floor use Java moss, and include lots of floating plants as this will give the fry some cover until the female can be removed. Gestation takes from 4 to 6 weeks.

The fry can be fed on Brineshrimps or powdered flake food, they don't need liquid food because they are to big when born. If well cared for (lots of water changes and good quality food) they will be big enough to sell at 10 to 12 weeks.

There have been reports of female Swordtails becoming male, they can develop a "sword" but it is uncertain whether they actually become fully functioning males.