These fish do very well in the harder, more alkaline waters that come from the taps in most parts of this country. They appreciate, and some species require, the addition of a small amount of salt in their water. While they will accept any and all foods that are small enough for them to swallow, these fish are primarily carnivorous, feeding on insect larva in the wild. In fact, members of this family often play important roles in mosquito control programs. They will thrive much better if you give them a little "meat" in their diet. The popular mollies are an exception and do best with the addition of vegetable matter to the diet.
The outstanding feature of these fish is their productions of live young. The fry are large and can eat within minutes of birth. They will reproduce in a community tank. However, the parents will quickly eat any young they can find. If you wish to save more than a few of the fry, steps need to be taken almost immediately after birth to separate the parents from the young.
Platies and Swordtails belong to the same Genus which means they are closely related and in most cases they will interbreed quite freely. And most of the modern fancy varieties originate from various crosses between the two along with some selective breeding. Guppies and Platies though, belong to different Genra making interbreeding a lot less likely if indeed it happens at all.
It's interesting that Platies and Swordtails will often interbreed to produce hybrids. In fact most Platies and Swordtails sold as pets have genes from both species. Click here for more about Platies, and here for more about Swordtails.
Most Livebearing Toothcarps prefer the pH to be above 7, ideally between 7.2 to 7.8 and the GH 12 to 30. They don't really like soft acidic water like the small Tetras and this should be kept in mind when choosing fish. Most are quite adaptable so if they are acclimatised properly they will accept a variety of conditions. Most, but not all species of Mollies need to have a little salt added to their water at the rate of 1 teaspoon per gall. It is important that marine salt is used and not table salt intended for human consumption.
Platies Swordtails and Guppies do not need any salt adding to the water and it should not be used with them except as a treatment for some diseases.
Today most health problems seem to be related to inbreeding or just poor breeding when unsuitable adults have been used. Followed by keeping them in unsuitable conditions (soft acidic water). When the conditions aren't right they seem more prone to fish TB than most other fish.
To ensure good health buy fish which are young and healthy, if there are any in the same tank which show signs of inbreeding reject all the fish in that tank. The signs to look for to avoid are - bent backs which makes the males swim as though their tails were to heavy, kinked spines, missing gill covers, slight eye deformities ect. If the fish are from good stock and kept in the right conditions they normally remain quite healthy.
Livebearers are quite peaceful fish, usually ignoring tank mates completely. Some care must be taken with guppies - the long colouful tails of male guppies can be tempting for any fish prone to nipping. If male and female livebearers are kept together, there should always be more females than males. Males of most species will chase the females incessantly - even females of other livebearer species. Having a ratio of two females to each male will ensure that no one female is constantly chased. Alternatively, males can be kept without females.
An order of fish with eight families and numerous species of both egg-laying and livebearing fish. It includes two suborders, adrianichthyoidei (egg layers) and cyprinodontoidei (egg layers and livebearers). The latter suborder comprises cyprinodontidae (egg-laying killifish), goodeidae (mexican livebearers), jenynsiidae (jenynsiids), anablepidae (four-eyed fish), poeciliidae (livebearers). Of the suborder poeciliidae, the guppy and molly belong to the genus poecilia.