Guppies, Platys, Mollies, & Swordtails
Livebearers Make Interesting Additions to the Home Aquarium
Oct 11, 2009
Guppies, platys, mollies, and swordtails have become favorites in the aquarium hobby. These fish are easy to care for, are brightly colored, and easy to breed. Here we will look at how to care for these fish, as well as how to care for their offspring.
Guppies
The guppy, or fancy guppy (Poecilia reticulata) grows to 5 cm, with males being much more colorful than the females. Guppies are peaceful community fish.
Though originally from South America, most guppies available for sale are from Asia. This means they should be kept at higher temperatures (25-29º C), and have a bit of aquarium salt (one tbsp. for every 5 gallons) added to their tank in order to stay healthy.
Platys
Platys (Xiphophorus family) come in many colors and varieties. They grow to 5-7 cm, and like water in the 22-26º C range. Due to their similar coloration, it can be hard to distinguish male platys from females. Females are slightly larger and rounder than males.
The best way to distinguish the sexes of platys is to observe the fins on their underside (see third picture below). The male has a gonopodium, meaning that the fin in the center is elongated and pointed. Females, when pregnant, have a gravid spot, which is a black area at the end of the abdomen. All live bearers share these sexual characteristics.
Mollies
As with platys, mollies (Poecilia family) come in many different colors and varieties. Some people may have trouble telling the difference between mollies and platys. Mollies tend to be larger (5-10 cm) and have more solid colors (ie. all black, all white, all red, white with black spots). They like temperatures of 21-28º C, and like a tablespoon of salt for every 5 gallons of aquarium water. Mollies can even survive in full marine set-ups.
As with platys, the best way to sex mollies is by looking for the gonopodium of the male, and the lack thereof, and gravid spot, of the female (see previous section on platys). Mollies are peaceful fish, and make good additions to the community aquarium.
Swordtails
Swordtails (Xiphophorus helleri) come in many different colors and varieties. Growing to sizes of 5-10 cm, swordtails like temperatures of 22-26º C, and are peaceful community fish. It is easy to tell males from females, as the males have the characteristic "sword" at the end of their tail. To be sure though, always look for the gonopodium.
Breeding of Livebearers
Breeding live bearers does not take much effort. Most livebearers are pregnant from the time they are purchased. Ensuring that the babies reach adulthood though, is another story.
As the name suggests, livebearers give birth to free swimming fry. They can have 4-60 babies, 3-4 times a year. Unfortunately, the fish in the tank, including the parents, will eat the baby fish. A pregnant female should be placed in a breeding trap, which is a clear plastic box that allows baby fish to fall through slots into a compartment where adult fish can not eat them. The baby fish should raised in a separate container until they are large enough to avoid being eaten.
Live bearers appreciate well planted aquariums, as this provides them with cover and makes them feel safe. Males should have at least 2-3 females available to them. This prevents the females from being overworked, and also prevents competition between males. To ensure that the pregnant females and their fry are healthy, feed them a variety of foods. Flake and freeze dried food should be offered, as well as diets that contain spirulina algae. Frozen foods such as brine shrimp and blood worms are also great choices.
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