Some fish are a pure delight to keep and breed. You provide a clean well filtered tank, some hiding places, (among the plants), a variety of nutritious foods and they do all the rest. The beautiful livebearer, Chapalichthys pardalis is one of these. They come from Mexico and the genus name, Chapalichthys, is derived from the Chapal lagoon, (Mexico's largest natural lake). Ichthys simply means fish. The species name, pardalis, is Greek for the spots on a panther or leopard. Their bodies are covered with circular black spots. Since they are part of a family of livebearers commonly called Goodeids (GOOD-EE-IDS) or, if you hail from Australia you might say (GOOD-EYE-IDS), a common name might be Leopard Goodeid. If that's too hard for you, call them Leopard Goodies.
We have wanted this fish since we first saw a splendid male specimen in a show in Brantford several years ago. Unfortunately, not many hobbyists keep Goodeids. I suspect that they get stuck with a bag of Xenotoca eiseni, sometimes called Mexican livebearers or Red-tailed Goodeids. One experience with those amazingly hardy, rough, tough and endlessly prolific fish can cause future negative reactions whenever goodeids are mentioned. The red-tailed Mexican, like Tilapia of the cichlid family shouldn't be sold without a warning on the bag. The Leopard Goody and most of the rest of the family provide a very different experience.
Luckily we found a bag of young pardalis at the Hamilton auction last fall. One of the males, (you can tell by the notched anal fin), had a bent spine and was culled out but that still left us with two males and a smaller female. Males eventually get to around 2 1/2 inches with females a little larger and ours was only about 1 1/2 inches but she soon proved that she was mature enough to give birth. Within a month she produced 4 large, (1.2 cm), fry. For breeding award purposes we ignored these because she had obviously been pregnant when we bought her. We haven't kept careful records yet but gestation seems to take the better part of 2 months.
The pardalis, like other goodeids, don't have huge spawns because they are truly viviparous. For most of the Poeciliids, (Guppies, Swords, etc.), livebearing simply means that the eggs are fertilized and hatch inside the female fish before being expelled. Their babies are very small but numerous. Goodeid eggs are nourished by a placental-like structure called trophotaenia. They spend a longer period of time inside the mother, grow much larger and are fewer in number. (Twenty would be a large spawn in most cases.)
The other difference is that male goodeids do not product packets of sperm. In poeciliids these packets can be stored by the female making a sequence of pregnancies possible without a male being present after the first. Goodeids have to be impregnated each time.
On that subject, the mating dance of the pardalis is quite intricate. Unlike the gonopodium of the Guppy et al, the notched anal fin of these goodeids doesn't seem to play an essential part. Scientist who study such things have actually removed it and impregnation still happened.
Looking very much like the males except for their notched anal fins and the bright yellow bands near the edge of their caudal fins, our young female has produced a second spawn. She had 11 large fry this time and, typical of this species, they were not bothered by the adults. (I told you they were easy.)
The inevitable question is, "Can they be kept in a community tank?" We haven"t tried but everything we've read suggests they can. Regular water that is not too warm suits them. They appreciate regular water changes and a variety of foods just like many other fish. They don't bother their own young so they likely won't attack other small fish. We'd recommend introducing other species to their tank cautiously and observing carefully. It's fun to watch them anyway.
The 'caution' comes from our experience many years ago with a similar species called Ameca splendens. They are also a beautiful and basically peaceful species of goodeid. However, for reasons known only to the fish, they will sometimes attack Corydoras catfish, (particularly the albino aeneus), and trim off parts of their dorsal and caudal fins. We discovered this unfortunate character flaw only after selling some to a local pet store where they were put in a tank with some Corys. Oops!