Emeraldking-aquatics livebearers


This genus exists of swordtails and platies (also called platyfish). The name "Xiphophorus " is a composition of two greek words, meaning "dagger" and "bearer". Looking at swordtails, you'd expect it to be referred to the swordshaped tail but it actually refers to the gonopodium.
Note: Not all swordtail males do develop a sword and with some platy strains males can develop a very short swordtail. With this being said, the sword (elongated lower finrays of the caudal) seems to be a sexual preferable trait to female swordtails and female platyfish. It's known that swordtails and platyfish are able to interbreed with another. It's also known that female livebearers decide wether a certain male is allowed to mate with her (no matter how often a random male may chase her and even tries to aim his gonopodium in her direction). But if a male swordtail or a male platy with a sword is present, she'll most likely prefer such a male to be her mating partner instead of a male with no sword. Which makes it also more likely that a female platy will choose to mate with a swordtail than with another platy when both species are kept together in one tank. So, in reference to mating selction in general, female of Xiphophorus species prefer swords of male swordtails and platyfish more than the coloration on the male's body.

Swordtails inhabit waters ranging from Belize, Honduras, Guatemala and mainly Mexico. Platies however occur only in Mexico. Swordtails do occur in freshwater but also in brackish waters. They can even get used to marine water just like mollies. But just like guppies, swordtails and platyfish were also introduced by man to other waters all over the world. For a lot of swordtail strains do occur in higher situated areas where it can be a lot colder which makes them excellent inhabitants in other colder areas. This tells us as well that we should label swordtails as being subtropical instead of tropical.
There are so many different swordtail and platy strains in the wild. The fancy swordtail strains we know are all derived from the Xiphophorus helleri and the fancy platy strains from the Xiphophorus maculatus and the Xiphophorus variatus. But again, besides these three... there are way more wild strains of swordtails and platies.
All swordtail and platyfish species found in other areas on this globe are introduced by man and are therefore feral strains.

Overhere a summary of all wild caught swordtails and wild caught platyfish (which were used for research) and their GPS locations as far as known of course:
Overhere a phylogenetic tree of all known wild Xiphophorus species:
Note: Males of the xiphophorus species may develop a socalled "pseudo gravid spot". This phenomenon happens mostly with platy species in comparison to swordtail species. Mostly such a pseudo gravid spot will be developed during or after the transition of the anal fin into a gonopodium. It hardly happens before the anal fin's transition.This has got nothing to do with a female turning into a male. For that's a different story.
A gravid spot of a female is the most translucent part of the skin while a pseudo gravid spot is developed in the skin (and absolutely not translucent). But once a pseudo gravid spot is developed, it will never fade nor disappear.
Above: An adult male Xiphophorus evelynae.
Note: Once a pseudo gravid spot has shown on a male's body, it will never dissappear.

Sex change:
Xiphophorus species "can" be born with both male and female gonads. Generally spoken, an initial male will absorb the female gonads and an initial female will absorb the male gonads while growing up. But in some way this absorption doesn't always seem to happen the way it suppose to be. Which makes it possible that female specimens can change gender. Even when she's been pregnant before. But in that case, the female will keep her gravid spot. And the transformed specimens will be functional males when it comes to reproduction. But yes, also old females can change gender after they've had their defininite last batch of fry. In general, such a transition will take place after a certain trigger (only possible as long as such a female is an Aa genotype). An example could be an unbalanced male/female ratio within the group or even a lack of hiearchy within the group. But there are more triggers to establish a sex change.
Males however can not change gender for the transition of the anal fin into a gonopodium is irreversible. In the past I've put pregnant females seperate. They've dropped fry and some changed into functional males. I've put some together with young virgin (but already sexually mature) and they were impregnated by transformed females. The offspring were fertile.
Of course this is written in a way that it's understandable for an average person who's just interested in how this works. To give away a bit more of information, I do have to mention that with Xiphophorus species we're not dealing with just 2 sex chromosomes (X and Y) like most animals have but with 3 sex chromosomes: W, X and Y.
Note: A sex change does not only happy to Xiphophorus species. It can also happen to a number of other kinds of livebearer species. But not with all kinds. But it happens mostly with Xiphophorus species as best known livebearer family.

If there's a lack of males or even no males within a group but there are fry present, you'll notice that there will be fast developing young males. These males stay small in comparison to an average male's body size. This is to ensure the reproduction and the exsistance of the species. What's also remarkable with early males is that the majority of their offspring will be male at an average temperature. With late males a majority of female offspring will be the result (and again at an average temperature).
For further info, I'd like to refer to the introduction chapter by clicking the button below:
It seems that not all aquarists know the difference between a maculatus platy and a variatus platy. Not the coloration, pattern nor the finnage will make the difference in appearance to determine a platy to be a variatus or a maculatus.
It's the bodyshape that's the crucial difference (besides DNA) in both Xiphophorus species. The picture below will show the main differnce to a layman.
And it also seems that not all aquarists know the difference between a maculatus platy and a common swordtail. Not the coloration, pattern nor the finnage will make the difference in appearance to determine a specimen to be a platy or a swordtail.
It's the bodyshape and size that make the crucial differences (besides DNA) in both Xiphophorus species. The picture below will show the main differnce to a layman.


Wild platies

Xiphophorus variatus La laguna
This wildstrain can be found close to the east coast of Mexico (state of Tamaulipas). The habitats has got a wide range from southern Tamaulipas, eastern San Luis Potosi and northern Veracruz. In general they inhabit  slow flowing till still waters.
This species does well at lower temperatures and after an average gestation a female will drop between 5-20 fry in general. Good thing is that also this strain will leave their newborn fry at ease. So, creating a colony without a threat of fry eating is potential. 
Despite of the fact that males tend to become very colorful, it will take quite long before a male will have its final colors. But not all males will be that bright colored. For it's mostly the dominant males which will become the best colored specimens within the colony. Females don't have that much color but they're well-speckled for that matter. And some females do tend to have somewhat yellow in their fins.
Above: A juvenile male which is starting coloring up.
The ones in my possesion are descendants from the wildcaughts by McAllister.

Xiphophorus variatus Puente escalanar
This beautiful wild species originates from Puente escalanar, Veracruz in Mexico and were first collected back in 2002. What's remarkable is that this species has a couple of phenotypes. But most essential is that both genders show a crescent mark on the caudal penducle.  There are phenotypes that have vertical bars on both sides of the chest and there are specimens that are spotted. The body color ranges from greyish till yellowish-golden.
The crescent they show on the caudal penducle is not alwyas very clear. Some have a yellow crescent.
Xiphophorus meyeri
The Xiphophorus meyeri (named after M.K. Meyer, author of livebearer related articles) belongs to the Northern platies. It's also known as Muzquiz platy and Xiphophorus marmoratus.
This platy species has solely been found in two connected ponds in the town of Muzquiz. It's located in the north of the state of Coahuila in the north of Mexico. The waters they inhabit are heavy vegetated.
The Xiphophorus meyeri is listed as being endangered.
The  species knows two varieties: A dark splotched one (marbled) and a non-splotched brown one. Both occur in the same population. But note that the marbled one is born without the splotches. Those occur while aging.
They tend to grow up between 3,5 - 4,5 cm in size. Keeping them at moderate temperatures is sufficient to keep them well. But these platies are a bit  timid and will hide more than the average platy. So be sure they do have sufficient hidng spots.
Further on to keep them well, it's important that a water change will take place regulary.
Xiphophorus evelynae
A wildstrain platy close related to the Xiphophorus variatus is the Xiphophorus evelynae. This strain is also known as Highland platy.
This platy is mainly found in the Rio Tecolutla stream.
This species prefers densely vegetated tanks to hide and sufficient swimming space for they tend to be vividly. Despite of their vividness, they're real friendly fish. 
In general they're greyish till lightbrown bodied with some spots on their body. They do show some yellow in their fins.
Above: An adult male.
Below: Two adult females.
It's a profilic kind of fish which doesn't seem to chase their fry. Also with this strain I do keep the new offspring with the adult fish. 
While doing well at lower temperatures makes this a very easy to keep type of fish. A real good contender to keep outdoors during spring and summer.  

Xiphophorus xiphidium
This species mentioned is also called "One spot platy".
This platy is endemic to Rio Santa Engracias at Tamaulipas in Mexico. It's a platy which has got a short bottomsword unlike other platies. It's a vey easy and hardy fish to keep. The name "One spot"seems very obvious in this case.
When males age they tend to get a hump on their backs and tend to develop a pseudo gravid spot. Further on they can also develop a couple of vertical bars on both sides of their body. Males size up to 4cm and females up to 5 - 6cm.
Below: A juvenile couple of Xiphophorus xiphidium.
The one spot strain which I'm keeping came from a generation wild caught fish in 1978. And there was no influence of other platy strains involved.
Above: An adult female and a juvenile male (the anal fin is already changing into a gonopodium)
There are also two other variations of the Xiphophorus xiphidiumcalled "Two spot platy" and "Crescent platy". The two spot platy is to be found in Rio Purification and the crecent platy in branches of Rio Soto La Marina.
Below: A small group of Xiphophorus xiphidium crescent.
Above: Two Xiphophorus xiphidium two (twin) spot.
Xiphophorus milleri
This platy is also called "Catemaco platy".
This species is endemic to the Papaloapan ecoregion (state of Veracruz)  in Mexico. This platy occurs in shallow tributaries of Lake Catemaco and in shallow mouths (brackish water) of inlets along the shoreline.
It's a yellow bronze bodied paty with speckles and mostly a crescent mark at the rear. There's a real difference in body build in comparison to the xiphophorus maculatus. 
There are also darker bodies males which seem to be also smaller than their bronze coloured relatives. Those darker bodied ones came to adulthood too fast (determined on the Y-chromosone). While regular males size up to approx. 4cm, these dark males will size up to approx. 2,5cm. Females however can size up to 5cm.
After a gestation of 3,5 - 4 weeks a number of fry will be born between 10 - 40. The adults will hardly chase their offspring. 

Xiphophorus maculatus, Chuco's place
A wild Xiphophorus maculatus platy species found in a small lake at Natural Park Biosphere Reserve Pantanos de Centla in Mexico is the following maculatus species as shown below.
The ones I got came from Kees de Jong (friend, author, co-editor at Poecilia Netherlands and a huge wild livebearer enthusiast like me). He caught them back in 2019 when he went on an expedition. He caught them from a small lake called "Chuco's place"(coordinates: 18.37166 - 92.69411), named after a commerical cichlid collector named Chuco. Remarkable is that this small lake is almost completely covered with water lettuce (Pistia stratiotes) and crocodiles are present overthere. In this lake occur as well Pseudoxiphophorus maculatus, Gambusia sp. and Dormitator maculatus.
 Above: An adult female.
Below: An adult male.
This X.maculatus version is grey bodied. Both genders have a round black spot on both sides of the shoulder. On the caudal penducle is a dark pattern to be seen (which is called a Mickey Mouse pattern or marking). This specific marking is also to be seen in several fancy strains of the Xiphophorus maculatus (the commercial name for such platies is Mickey Mouse platy and comes in several body colors). Btw, there are several kinds of wild platy strains that have a marking (shape may differ) on the caudal penducle.
Despite of the fact that these are wildcaughts, they seem pretty hardy. No problems whatsoever keeping them in captivity.

Fancy platies

When it comes to fancy platies, there's a whole variety of them. All fancy platies are derived from the Xiphophorus maculatus and the Xiphophorus variatus. The bodyshape of both species (X.maculatus & X.variatus) has stayed the same as their wild ancestors. Besides color and pattern, also the finnage can be different with fancy platies. For instance, hifin platies like the wagtail female shown below:
Maintaining fancy platies won't take that much effort. They're quite hardy and are omnivores. So, they eat almost everything that's offered to them.
Coral red platy
The coral red platy is one of the best red colored platies there is. A good specimen has a deep intense dark red colored body. Some white or blue may be shown in the finnage (on the edges). There's also an old strain from Berlin (Germany) that does even have a blue shine on te body when the light hits the fish.
By the way, the color red is not specifically a fancy trait. For in the wild there are a number of strains that do show a red coloration. But not that intense. The two pictures shown below show two different wild platy strains. Picture 1 shows a pale red wild platy. PIcture 2 shows a wild platy with pale red markings.
Bumblebee platy
Like the name already suggests, this strain has markings that resemble the pattern of a bumblebee. Most have a golden-bronze body with dark brown till even black patches randomly on their bodies.
A variety of this bumblebee platy is the calico bumblebee platy. They show more spots besides the dark patches and a blue shine. Like the ones in the video and picture shown above.
Blackamoor platy
This is a black platy but with translucent finnage. Note that this is not the same as the commercial strain "green lantarn". For the green lantarn platy has got a very dark blue body with translucent finnage. The blackamoor platies can have black finnage as well but those have a high chance to develop tumorous spots.
Some finrays can also be black. The japanese call this "shimi".
White platy
There's also a white fancy platy strain. I haven't been able to get my hands on white platies with white finnage nor couldn't I breed such a total white specimen.  I only was able to breed white platies with translucent finnage.
'This is not an albino platy! This is a leucistic platy (white body with black eyes)
Note: Maculatus platies can grow up larger than most people think. 8-10 Cm are not an exception. If the conditions are right, they can grow up massively.
Mark at the caudal penducle
There are several fancy maculatus platies available. One that I'd like to mention is the socalled Mickey Mouse platy. This kind of platy has derived its name of the head and ears of the Disney character Mickey Mouse. And more like the shape of those Mickey Mouse caps that children can get at those Disney parks all over the world. Many of us know this kind of platy which comes in several colors. But actually, that mark on the caudal penducle is not a fancy trait but a wild trait.
Below: The Mickey Mouse trait. This trait has been crossed into swordtails as well.
The marking on the caudal penducle of wild maculatus platies does differ per wild strain. The picture above shows 4 different kinds of wild maculatus platies with different caudal penducle markings.
Variatus platy
Also with variatus platies, there's a whole variety available on the market as a fancy species. The most known variety is the socalled parrot variatus play. Some are shown in the two pictures below:
Like already been mentioned by me, there are much more color and pattern forms of the variatus platy. Here are some different phenotypes:
For more fancy platy strains, I'd like to refer to the Legend chapter by clicking the button below: