Girardinus metallicus (Poey, 1854)

Etymology:                 Girardinus after the French – American ichthyologist Charles Girard

metallicus referring to the metallic body colouration.

First description:        Poey F. 1854.

Los guajacones, poecesillos de agua dulce. In Poey, F., Memorias sobre la historia natural de la Isla de Cuba.

Havana, vol. 1, pp 374 – 392, figs 8-11.

Common name            :           Metallic livebearer, Metallic Topminnow

Synonyms:                  Girardinus garmani Eigenmann 1903

Girardinus pygmaeus Rivas 1944

Type Locality:                        Botanic Gardens, Havana, Cuba.

Distribution:               Costa Rica, Throughout Cuba, except easternmost area at 200-300 m elevation.

History:                      Reports suggest the first import for the aquarium trade was made in 1906 by W. Schroot of Hamburg.

Habitat:                      It can be found in streams, ponds and ditches. The water is commonly stagnant and often brackish.

Inhabits ponds, lakes and streams. Prefers clear, stagnant or very sluggish water.

Size:                            Male 5.0 cm, Female 9.0 cm

Description                 Girardinus metallicus has a streamlined head and body with a superior mouth. The dorsal, pectoral, and caudal fins are medium length and rounded. Females have longer, deeper, more rounded bodies than the males with rounded anal fins.

Colour/Pattern:          There are two known colour variants for this species the better known ‘black-chin’ and a gold belly form.

Black chin – males have a black line starting from the mouth from the mouth and continuing through the underside of the body (including the gonopodium) and can reach the caudal fin, some specimens can have further black colouration which in some circumstances envelopes the whole head.

Gold form – males have a gold underside extending from the rear of the belly to the caudal peduncle.

The females for both variants look the same,

Bodies and heads range between translucent silver to a pale gold to olive colour. Iridescent silver diamond-shaped bars along the lateral line.

 Dorsal fin has a black spot at the bottom centre of the dorsal fin. Males have a deep overall metallic gold sheen, making the silver diamonds appear brighter and larger than on the paler female.

Behaviour:                  Peaceful, will predate fry. Likes to swim in the upper part of water column

Husbandry:                 Water should be medium hard and alkaline with a gentle flow, a sponge filter or something of that ilk is perfect. A temperature of 24º to 26º should be aimed for

Girardinus metallicus are omnivores and enjoy live or frozen foods, supplemented with algae flakes and small pellet food.

A well planted tank comprising of a substrate of sand/gravel and plenty of surface cover will help this fish to acclimatise and feel secure. Hiding places will also be advantageous.

Breeding Notes:         As with other poeciliid species, the males are known for their persistent behaviour so a ratio of at least 2 females per male is recommended.

Gestation takes around 24 – 28 days and broods of between 15-30 fry can be expected and adult fish will predate on the young so plenty of plant cover is required to provide shelter for the fry.

References:                Wischnath, L., 1993 – Atlas of livebearers of the world.

Seriously fish                                                 www.seriouslyfish.com

                                    Badmans                                                        badmanstropicalfish.com

Lee, D.S., S.P. Platania and G.H. Burgess, 1983. Atlas of North American freshwater fishes

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Xiphophorus couchianus (Girard C. 1859)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

couchianus after Lieutenant D.N. Couch.

First description:

Girard C. 1859

Ichthyological notices, 41 – 59.

Academy of Natural Sciences Philadelphia. No.11: 113 – 122.

Synonyms:

Limia couchianus Girard 1859

Common Name

Monterrey Platy

History:

Described by Girard in 1859 as Limia couchianus & later placed in Xiphophorus.

A female was used as a holotype measuring 41 mm. This was collected in the San Rio Juan in the area of Cadarecta & Monterrey, Nuevo León State, Mexico.

Group:

Xiphophorus couchianus is one of the three northern platys that belong to the Rio Grande platy subset consisting of consisting of X. couchianus, X. gordoni and X. meyeri.

Type Locality:

Rio San Juan, Cadarecta and Monterrey, Nuevo León State, Mexico.

There is some doubt as to the validity of this type location as there is a town named Cadereyta 35Km east of Monterrey.

Distribution:

Extinct in the wild

Populations:

Huasteca Canyon (Nuevo León State, Mexico)

Habitat:

Headwater streams, spring pools & rarely in sluggish flowing streams & ditches. The base is mostly clay & mud with a few areas of rock. Aquatic plants are quite dense with marginal plants near the banks.

Size:

Males: 30 mm, females: 40 mm

Colour/Pattern Variability:

The upper part of the body is dark brown, the scales have darker edging to give a net like appearance. The lower part of the body is off white.

The dorsal and anal fins have several dark crescents on them. All other fins are clear.

Behaviour:

A shy species and secretive species that like plenty of plant cover to hide in.

Husbandry:

A well planted aquarium with a temperature of 24°C and regular small water changes, although fairly tolerant of water conditions a sudden change in pH will kill this sp.

This species is reported as short lived and only expected to reach 12 months of age.

Breeding Notes:

Older females are known to produce weak young which have a high mortality rate. Brood sizes are reported at an average of 20 but 40 has been recorded in young adult females.

General remarks:

The original populations from the Huasteca Canyon died out in 1964 when the springs dried out due to excessive water pumping lowering the water table.

 A Xiphophorus species was discovered at Apodaca 20km northeast of the centre of Monterrey which was believed to be an undescribed sp. possibly a spotted form of X. couchianus (markings reminiscent of X. meyeri) or even a new species. Unfortunately this species has also died out and as the type specimens of X. couchianus cannot be found comparisons between the two species cannot be made.

References:

The Genus Xiphophorus in Mexico and Central America – Klaus D. Kallman and Steven Kazianis

Platies and swordtails – Derek and Pat Lambert

Photograph courtesy of Dave Macallister

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Xiphophorus xiphidium (Gordon 1932)

Etymology:

Xiphophorus: Greek, xiphos = sword

+ Greek, pherein = to carry

Xiphidium: Greek, xiph from xiphos = sword. Latin, idium = diminutive

First description:

Dr. Myron Gordon going on expedition. Aquatic Life 15: 287–288. (1932)

Synonyms:

Platypoecilus xiphidium – Meek, 1904.
Platypoecilus maculatus – 1913. 
Platypoecilius variatus -1932.

Xiphophorus variatus xiphidium – 1960

Common name:

Spiketail platy

History:

Original collection by Gordon, Creaser, and Ostos on April 25th 1930

Group:

Xiphophorus xiphidium is one of the northern platys consisting of X. variatus, X. evelynae, X. xiphidium, X. couchianus, X. gordoni and X. meyeri.

Type Locality:

Río Corona at La Corona, 15 miles north of Ciudad, Victoria, Río Soto la Marina system, Tamaulipas, Mexico

Distribution:

Found throughout the Rio Soto La Marina system, including ponds and irrigation ditches close to the river system.

Populations:

Rio Purification

Rio Santa Engracia (Rio Corona)

Habitat:

Inhabits tranquil zones of slow-flowing waters of ditches, spring areas, marshes and ponds.

Size:

Males 30 mm, Females 40 mm

Distinguishing Characteristics:

A deep bodied species with a high back and a stubby tail, a small sword or spike is present on the mature males.

Colour/Pattern Variability:

Males

The basic body colouration is greenish brown on the top, becoming white on the belly, in males as they reach sexual maturity they begin to develop their full colouration.  This can be quite variable and well coloured specimens will have their basic body colour overlaid with purple and dominant males can develop a number of vertical black bars along the upper flanks. Sometimes black spots will also develop and may become so profuse that the whole of the middle region of the fish will be purple with a black saddle.

The caudal peduncle has a variety of markings from nothing to a full spot encompassing the caudal peduncle. The more usual markings found in the hobby are two spot, crescent and single spot.

The dorsal fin is a pale yellow to clear in colour and has a crescent marking within.

All other fins are pale yellow to clear in colour.

Females

The basic body colouration is greenish brown on the top, becoming white on the belly. Sometimes small black spots will also develop on the flanks.

The caudal peduncle has the same range of markings as the males.

The dorsal fin is a pale yellow to clear in colour and has a crescent marking within.

All other fins are pale yellow to clear in colour.

Behaviour:

Generally a peaceful fish, however a dominant male will guard a territory and protect it from other males. The females are free to roam between territories.

Husbandry:

A well planted tank with regular water changes and a diet that includes some live food. Temperature range is from 18C to 25C, with Dereck Lambert recommending 23C

Breeding Notes:

Broods are born on a monthly cycle and number from 20 to 35, provided there is plenty of cover and food then this species can be flock bred.

Remarks:

Dereck Lambert in Platies and swordtails states that the caudal markings have been associated with certain populations, but in fact, fish with all the tail-spot patterns can be caught in the same net in the wild.

References:

Donn E. Rosen: Middle American poeciliid fishes of the genus Xiphophorus.Bull. Fla. St. Mus. Biol. Sci. 5 (4): 57 – 242.

Derek and Pat Lambert: Platies and swordtails        

Photograph courtesy of Dave Macallister

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Xiphophorus evelynae (Rosen 1960)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

evelynae: named after Mrs. Evelyn Gordon.

First description:

Donn E. Rosen 1960.

Middle American poeciliid fishes of the genus Xiphophorus.

Bull. Fla. St. Mus. Biol. Sci. 5 (4): 57 – 242.

Synonyms:

X.variatus evelynae Rosen 1960

Common name:

Pueblo platy

History:

Collected by M. & E. Gordon on the 6th April 1939.

Originally collected by Mrs. Evelyn Gordon in 1939.

First UK import is recorded in April 1979 by Howard Preston, who met Dr. A. C. Radda in Puebla, Mexico. Radda had been collecting & gave him some fish. No data is available as to the collection site.

Group:

Xiphophorus evelynae is one of the northern platys consisting of X. variatus, X. evelynae, X. xiphidium, X. couchianus, X. gordoni and X. meyeri.

Type Locality:

The confluence of the Rio’s Xanthophyll & Necaxa at Tepexic, Mexico.

Distribution:

Restricted to a series of cataracts near the village of Necaxa (also known as La Mesa). This is an area approx. 1220 metres above sea level.

Populations:

Rio Necaxa (Puebla State, Mexico)

Habitat:

Restricted to springs and the power company’s reservoirs around the village of Nexcaxa. Larger more colourful specimens were found at the base of the water fall 580m below the reservoirs, but were wiped out by torrential flooding caused by a hurricane. The species have never returned to the waters below the waterfall, possibly because the water that flowed from the reservoirs and became the waterfall are now deflected to the power company’s hydroelectric generators. Other livebearers such as Poecillia sphenops and pseudoxiphophorus bimaculatus have managed to re-established colonies there.

Size:

Males: 40 mm, females 50 mm.

Distinguishing Characteristics:

The body shape of X. evelynae is similar to its’ close relative the X. variatus.

Colour/Pattern Variability:

Males

The male develops 8 to 12 thin black vertical bars, the body base colour ranges from a pale brown to a honey yellow. Some specimens have black speckling on the flanks.

The dorsal fin is an orange or yellow colour sometimes with darker crescents mid dorsal, the pigment fades towards the outside of the fin.

The Caudal fin is an orange or yellow near to the caudal peduncle and fades towards to outer parts of the fin.

All other fins are clear

Females

The body base colour is a pale brown colour, sometimes females develop some dark speckling on the flanks.

All fins are clear.

Behaviour:

Regarded as an active but peaceful fish.

Husbandry:

A Planted tank with regular water changes and some gentle filtration is generally all this species require. Lower temperatures are appreciated

Breeding Notes:

Regarded as an easy fish to breed, broods are born on a 4 weekly cycle and can number up to 50 robust fry. Parents will tolerate young in the tank but older females have been known to be cannibalistic towards them.

Fry are known to hide at the base level of the tank for the first few days.

Can be flock bred provided there is sufficient plant cover and food.

Remarks:

I have kept this species outside in a large tub throughout the summer. Prior to going outside I struggled to get these fish to look happy or even settled in. On collecting them from the tub after the summer and returning them to their aquarium I have found that they have positively thrived. The numbers have increased, their size and colour have improved and they themselves are happier than before. Some reports I have seen have stated that this species will survive at temperatures as low as 4C, but I am not sure I would recommend trying this.

 This is a species you should try as your first garden tub experiment.

References:

Middle American poeciliid fishes of the genus Xiphophorus.

Bull. Fla. St. Mus. Biol. Sci. 5 (4): 57 – 242.                                    Donn E. Rosen

Platies and swordtails                                                                      Derek and Pat Lambert

Fishbase

Wikipedia  

Young fish. Photo Tim Addis.

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The Northern Platies

Xiphophorus evelynae

Xiphophorus variatus

Xiphophorus xiphidium

Xiphophorus couchianus

Xiphophorus gordoni

Xiphophorus meyeri

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Xiphophorus continens (Zimmerer and Kallman 1988)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

Continens: Greek, conto = short + Latin, ensis, = sword

(Reference to the very small sword developed in males of this species.)

First description:

Zimmerer and Kallman 1988

American Museum Novitates Number 2975, June 27, 1990.

Monophyly and Geography of the Rio Panuco Basin Swordtails (Genus Xiphophorus) with

Descriptions of Four New Species

Mary Rauchenberger, Klaus D. Kallman and Donald C. Morizot

Common names

El Quince Swordtail

Synonyms

Xiphophorus sp. Nov. Zimmer & Kallman 1988.

Group:

Xiphophorus continens is one of nine northern swordtails and belongs to the Montezumae clade, consisting of X. montezumae, X. nezahualcoyotl, X. continens

Type Locality:

The Nacimiento of the Rio Ojo Frio at El Quince, north of Rascon, Rio Gallinas- Rio Panuco drainage, San Luis Potosi, Mexico

Collected on April 27, 1984, by K. D. Kallman and D. C. Morizo

Distribution:

Headwaters of the Rio Ojo Frio, north of Damian Carmona, Rio Panuco drainage, San Luis Potosi. Mexico

Populations:

Rio Ojo Frio, El Quince, San Luis Potosi. Mexico.

Habitat:

Fast flowing river, with high aquatic vegetation with a stony river bed.

Size:

Males 2.5cm, Females 3.5cm

Distinguishing characteristics:

It is a small, slender species, with a slender caudal peduncle. The sword is barely noticeable with a maximum length of 1 millimetre.

Colour/Pattern Variability:

A small slender species, the body colour is pale golden brown with a darker brown midlateral stripe. There are one or two less prominent zigzag stripes above the midlateral stripe. The underneath section is white from the mouth to the anal fin.

The dorsal and caudal fins are clear to pale yellow, all other fins are clear.

 Males do not develop a sword greater than 1 mm.

Behaviour:

Not a shy fish when settled, will happily swim around the front of the aquarium looking for food. 

Husbandry:

A well planted aquarium with a temperature of 21 – 22 degrees C

Breeding Notes:

After a gestation period of 24-28 days, female produces 10 to 20 young,

Remarks

The overall shape and appearance of this species is most similar to X. pygmaeus and was assumed to be closely related. Closer scrutiny has found that X. continens shares characteristics found in X. montezumae and X. nezahualcoyotl.

References:

Rauchenberger, Kallman & Morizot: American Museum Novitates Number 2975, June 27, 1990.

Monophyly and Geography of the Rio Panuco Basin Swordtails (Genus Xiphophorus) with

Descriptions of Four New Species                

Derek and Pat Lambert: Platies and swordtails                                          

Photograph courtesy of Dave Macallister

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Xiphophorus multilineatus (Rauchenberger, Kallman & Morizot 1990)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

multilineatus: Greek: multi-, many; -lineatus, line; in reference to the prominent vertical bars on the flanks.

First description:

Rauchenberger, Kallman & Morizot 1990

Rauchenberger, M., K. D. Kallman, AND D. C. Morizot (1990) Monophyly and geography of the Rio Panuco basin swordtails (genus Xiphophorus) with descriptions of four new species. American Museum Novitates 2975, 1–41.

Synonyms:

X. nigrensis Rosen, 1979

Common name:

High-Backed Pygmy Swordtail

History:

Collected by K. D. Kallman, D. C. Morizot, V. Borkoski, and G. Peters on February 17th 1979

Group:

Xiphophorus multilineatus is one of nine northern swordtails and belongs to the Pygmaeus clade consisting of consisting of X. pygmaeus, X. nigrensis and X. multilineatus.

Type Locality:

Rio Coy near its confluence with the Rio Tampaon, Rio P’anuco drainage, SLP, Mexico.

Distribution:

Rio Coy system, Rio Panuco drainage, SLP: throughout Rio Coy, Arroyo Tambaque, and Arroyo Oxitipa as far as Octzen.

Habitat:

Found in a fast flowing river with dense aquatic plant growth and overhanging shore vegetation.

Size:

Males: 25mm to 40mm,     Females: 40mm

Distinguishing characteristics:

A species with a four known size variations within the male range, the largest variant is the one most often in the hobby. X. multilineatus in its larger form is a small high backed form of swordtail with a medium sized sword of roughly ½ – ¾ total body length.

Colour/Pattern Variability:

Males

There are four size variants ranging from 25mm to 40mm, the larger males develop a high back and vertical barring on the flanks. All males have a body colouring of pale metallic blue and a single bold zigzag midlateral line, (present from birth). A black spot can be found at the base of the pectoral fins on all sizes of male except the smallest size variant. The scales above the lateral have a dark edge giving a net like appearance.

A caudal spot is present but only really prominent on the large males. The caudal fin is edged in black and has is generally clear. The sword length varies according to the size variant, the largest males can have a sword length equal to the body length and the smallest 1-2mm. The sword is distinctly upturned, particularly when small and the colouring does not reach the end of the sword, the sword is edged in black.

The dorsal fin is generally clear, there is a black edge and a black band one third of the way up the fin.

As with all of the Pygmaeus clade a yellow male form can be found, but in X. multilineatus this only exists in the smaller size.

Females

A basic body colour of greyish blue with a single bold zigzag lateral line. The scales above the lateral have a dark edge giving a net like appearance.

The dorsal fin is clear, there is a faint black edge and faint black band one third of the way up the fin.

Behaviour:

A timid species that spends much of its time hidden amongst the foliage.

Husbandry:

A large well planted with filtration, aeration and frequent water changes.

Breeding Notes:

Broods are born on a monthly cycle and number about 5 – 10, 20 being generally the maximum amount, fry are large and normally left alone by the parents.

References:

Rauchenberger, Kallman & Morizot: Monophyly and Geography of the Rio P’anuco Basin Swordtails (Genus Xiphophorus) with descriptions of four new species            

Derek and Pat Lambert: Platies and swordtails                              

Photo courtesy of Dave Macallister

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Xiphophorus nigrensis (Rosen, 1960)

Etymology:

Xiphophorus: Greek, xiphos meaning ‘sword’; Greek, pherein meaning ‘to carry’

Nigrensis: Latin, nigri meaning ‘black’; Latin, ensis meaning ‘to come from’.

First description:

Donn E. Rosen 1960.

Middle-American poeciliid fishes of the genus Xiphophorus.
Bull. Fla. St. Mus. Biol. Sci 5 (4): p 57-242.

Synonyms:

Xiphophorus pygmaeus nigrensis Rosen, 1960

Common name:

El Abra Pygmy Swordtail

History:

Collected by D.E. Rosen, M.S. Gordon and M. Gordon on January 19th 1957

Group:

Xiphophorus nigrensis is one of nine northern swordtails and belongs to the Pygmaeus clade consisting of consisting of X. pygmaeus, X. nigrensis and X. multilineatus.

Type Locality:

Nacimiento del Río Choy, San Luis Potosi, Mexico.

Distribution:

Only found in the Rio Choy.

Habitat:

Found along the length of the Rio Choy, more common at the mouth of the cave where the river originates from, the water at this point is clearer and the current stronger.

The Rio Choy is also known locally as the Rio Florido near the Cave. This river is the northern most tributary of the Rio Tampoan

The biotope is clear & fast flowing & originates from inside a cave under the El Abra Mountain. The biotope further downstream is reportedly slower flowing with dense aquatic plant growth especially near the banks.

Rio Choy, Rio Panuco basin, SLP, Mexico
Photo courtesy of Dave Macallister

Size:

Males 25 – 40 mm; females 40 mm.

Distinguishing characteristics:A species with a three known size variations within the male range, the largest variant is the one most often in the hobby. X. nigrensis in its larger form is a small high backed form of swordtail with a deep body and a medium sized sword of roughly ½ – ¾ total body length.

Colour/Pattern Variability:

Males
There are three size variants ranging from 25mm to 40mm. The larger males tend to be deeper bodied. The body colouration is greyish blue with a single bold zigzag midlateral line, (present from birth) but in fully mature males the colour becomes more of an intense metallic blue and the midlateral line will fade out.

The caudal spot is variable and when present really prominent on the large males. All other fins are generally clear. The sword length varies according to the size variant, the largest males can have a sword length equal to the body length and the smallest 1-2mm. The sword is distinctly upturned particularly when small, the sword has black edging and is clear except on some individuals it can be yellow.

The dorsal fin is generally clear, there is a black edge and a black band one third of the way up the fin.

As with all of the Pygmaeus clade a yellow form of male can be found.

Females:

A basic body colour of greyish blue with a single bold zigzag lateral line. All fins are clear, but the dorsal fin has a faint black edge and a faint black band one third of the way up the fin.

Photo courtesy of Ivan Dibble, taken at BLA 2004
Photo courtesy of Dave Macallister

Behaviour:

Shy at first but will become bolder as the colony expands.

Husbandry:

The Aquarium should be well planted with filtration and aeration.

This species is very susceptible to P.H. swings so all water changes should be small but frequent.

Breeding Notes:

Females drop on a monthly cycle. Brood sizes are relatively small being only 2 for smaller females & up to 20 for more mature females. These females are thought to be fertile between 3 – 8 months of age.
Large morph males sex out at 5 months.
It is important to remove virgin females from the brood & mate with the larger form males as the small form will become dominant with the loss of the larger form. Females are not affected by this sex-linked gene which is only known in males.

References:

Donn E. Rosen: Middle-American poeciliid fishes of the genus Xiphophorus.       

Rauchenberger, Kallman & Morizot: Monophyly and Geography of the Rio P’anuco Basin Swordtails (Genus Xiphophorus) with Descriptions of Four New Species                                              Derek and Pat Lambert: Platies and swordtails      

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Xiphophorus pygmaeus (Hubbs and Gordon 1943)

Etymology:

Xiphophorus: Greek, xiphos = sword + Greek, pherein = to carry

pygmaeus: due to it diminutive size

First description:

C.L. Hubbs and M Gordon (1943)

‘Studies of cyprindonont fishes. 19. Xiphophorus pygmaeus, new species from Mexico’ Copeia 1943(1):31-3

Synonyms:

Xiphophorus pygmaeus pygmaeus Rosen 1960

Common name:

Slender Pygmy Swordtail

History:

Collected by Myron Gordon and Salvador Coronado, April 14th 1939

Group:

Xiphophorus pygmeaus is one of the nine northern swordtails and belongs to the Pygmaeus clade consisting of consisting of X. pygmaeus, X. nigrensis and X. multilineatus.

Type locality:

 Río Axtla of Río Panuco system, at Axtla, San Luis Potosí, Mexico.

Distribution:

Rio Axtla system, Rio Panuco drainage, SLP: abundant in Rio Huichihuayan, less common in lower 9 km of Rio Tancuilin and upper 5 km of Rio Axtla.

Populations:

Rio Axtla

Rio Huichihuayan

Habitat:

X. pygmaeus is most commonly found in rivers or pools which have dense vegetation with overhanging banks.

Size:

Males 25mm – 30mm females 40mm

Distinguishing characteristics:

A very small slender form of swordtail with a very short sword. There are two male size variations. Ranging from 25mm to 30mm standard length.

Colour/Pattern Variability:

Males

A single bold lateral line runs from the eye. The colouration below the lateral line is white with a bluish tint, a pale blue stripe sits above the lateral line and the rest of the back is brown with the edges of the scales being darker giving a net like appearance.

A short sword of generally less than 2mm but never more than 8mm, the sword does not have black edging.

The dorsal fin in this species is short, both in height and base length, the fin is clear with a faint black edge and faint black band one third of the way up the fin.

As with all of the Pygmaeus clade a yellow form can be found. This Yellow form has been fixed within the hobby and can easily be acquired.

Females

A single bold lateral line runs from the eye. The colouration below the lateral line is white with a bluish tint, a pale blue stripe sits above the lateral line and the rest of the back is brown with the edges of the scales being darker giving a net like appearance. The females show a gravid spot

The dorsal fin is clear with an extremely faint black edge and an extremely faint black band one third of the way up the fin.

Behaviour:

A shy species that likes plenty of plant cover to feel secure.

Husbandry:

A small aquarium well planted with an air driven sponge filter or no filter but regular water changes. Plenty of Java moss should be on the bottom of the aquarium

Breeding Notes:

Broods are born on a monthly cycle and number about 5 – 10, fry are and normally left alone by the parents.

References:

Middle-American poeciliid fishes of the genus Xiphophorus.

Bull. Fla. St. Mus. Biol. Sci 5 (4): p 57-242.                Donn E. Rosen

American Museum Novitates Number 2975, June 27, 1990.

Monophyly and Geography of the Rio P’anuco Basin Swordtails (Genus Xiphophorus) with

Descriptions of Four New Species                             Rauchenberger, Kallman & Morizot

Platies and swordtails                                              Derek and Pat Lambert

Fishbase

Wikipedia

Photograph courtesy of Dave Macallister

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The Northern swordtails

The northern swordtails live in and around the Panuco river basin and are separated from the southern swordtails by a geographical dividing line known as the Trans-Mexican volcanic belt. The northern swordtail group is made up of three clades and these are the Montezumae clade, the Cortezi clade, and the Pygmaeus clade.

Please click on the title of the fish to see the profile

The Montezumae Clade

Xiphophorus montezumae

Xiphophorus nezahualcoyotl

Xiphophorus continens

The Cortezi clade

The Cortezi clade consists of three species X. cortezi, X. birchmanni and X. malinche and are regarded by many as some of the most beautiful fish within the Xiphophorus Genus. The swordtails themselves are medium sized swordtails and grow about 50 – 60 mm in length. They are not too difficult to maintain and they lend themselves to planted community aquariums as well as species only set ups.

Xiphophorus cortezi

The Cortes sword has many populations with some of them having males that have striking bright yellow dorsal and caudal fins with a body sporting a series of thin vertical stripes. The Cortes sword has the largest distribution of the clade which ranges from just south of the Rio Tampaon – Santa Maria axis to parts of the Rio Claro and tributaries of the Rio Calabozo. Within this range they can be found at altitudes of between 100 metres to 1200 metres although they are reportedly more prevalent at the lower altitudes. The habitat they are found in is generally free of vegetation and fast flowing.

Xiphophorus birchmanni

The birchmanni swordtail is also known by the common name of the ‘sheepshead’ swordtail. This reason for this common name is due to the large prominent bump that forms at the back of the head of mature males giving a similar profile to that of a sheepshead! The dorsal and caudal fins are a beautiful yellow colour which are scattered with a covering of small black spots. The caudal fin is most unusual as it doesn’t grow a sword or if it does it remains very small, but the dorsal fin (seemingly trying to compensate for the failing of the caudal fin) grows quite large in contrast and becomes almost sail like in appearance. The body shape is generally deeper than that of the others members of the clade and the flanks also show a series of  vertical stripes similar to those of the Cortes sword apart from being distinctly much broader.

The distribution of the birchmanni swordtail is also fairly extensive, ranging from the Rio Sans Pedro down to the Rio Tuxpan drainage incorporating the Rio Vinazco and the Rio Beltran. This species of swordtail is generally found at higher altitudes than the Cortes sword and has been found between the altitudes of 500 and 1000 metres. This species is generally found in a habitat of fast flowing water over a rocky / sandy substrate with dense vegetation.

Xiphophorus malinche

The malinche swordtail also grows a lump behind the head in the same fashion as the birchmanni swordtail, but this is not anywhere near as prominent. The colouring is similar to that of the birchmanni swordtail with a distinctive yellow caudal with a medium sized sword and yellow dorsal fin showing black spots. The body colour is also similar but does seem to have purple hue. Unlike the previous clade members the stripes on the flanks of the malinche swordtail are far more irregular, often at different angles to each other and sometimes broken in appearance.

The range of distribution for the malinche swordtail is at present relatively small due to the fact it has not yet been fully explored. Their current range includes the Rio Claro down to the tributaries of the Rio Calabozo.

The common name for the malinche swordtail is the Highland swordtail. This name derives from the altitude of the rivers and streams they inhabit. They are found at altitudes which range from 650 to 1300 metres. The habitat they can generally be found in is one of fast flowing water over a sandy substrate with dense vegetation.

The three species overlap within their respective ranges and hybrid populations do exist. Where the Cortes swordtail overlaps with either the birchmanni swordtail or the malinche swordtail it is at the higher end of the Cortes swordtail range and lower end of either the birchmanni or malinche swordtail range. Similarly when the birchmanni swordtail and the malinche swordtail ranges overlap it is at the higher end of the birchmanni swordtail range and lower end of the malinche swordtail range.

It is unfortunate that in recent times, the members of this clade apart from X. cortezi have been absent from the UK side of the hobby. Happily I am pleased to say that at recent events birchmanni swordtails have started to make a comeback and are already becoming more sought after. This is a trend that I hope will continue, and with luck (fingers crossed), malinche swordtails will also make a welcome return to the UK.

The Pygmaeus clade

The Pygmy swordtails are as the name suggests some of the smallest swordtails known within our hobby. The Pygmy swordtails form the Pygmaeus clade which is made up of three species (Xiphophorus pygmaeus, Xiphophorus nigrensis and Xiphophorus multilineatus), the three species live in the state of Sans Luis Potosi within the Rio Panuco river basin. The rivers these swordtails are predominately found in are the Rio Huichihuayan (Xiphophorus pygmaeus), the Rio Choy (Xiphophorus nigrensis) and the Rio Coy (Xiphophorus multilineatus). These rivers are formed in close proximity to each other by natural springs that surface in the Sierra Madre Mountains and although the rivers are formed and run closely to each other, there are no natural connections between any of them.

Xiphophorus pygmaeus

The pygmy swordtail is as the name suggests the smallest of the clade reaching a length of 30mm for males and 40mm for females. This species is well known within our hobby with many of us at one time or another keeping either the blue or yellow form, at the auctions this species is usually well represented and always popular.

The type locality for the pygmy swordtail is the Rio Axtla which was described as being a fast flowing river with little vegetation. This description was as you would expect with the information given became the model for how most aquarists kept this species for many years. Subsequent research has now shown that the pygmy swordtail is generally found in highly vegetative areas of slow moving water away from the main currents. These new findings have since altered the preferred method of maintenance to a well planted aquarium with moderate to little water movement.

The pygmy sword is found predominately in the Rio Huichihuayan, but they can also be found to a lesser extent in both the Rio Tancuilin and the Rio Axtla. The Rio Huichihuayan and the Rio Tancuilin merge together to form the Rio Axtla.

Xiphophorus nigrensis

The El Abra swordtail (Xiphophorus nigrensis) is only found in the Rio Choy, a deeper bodied fish than the pygmy sword with the larger type males reaching a standard length of 40mm with a sword of up to 30mm long. This species not always available at the auctions these days, however if you can provide the correct conditions for these fish, they are definitely worth keeping.

The River Choy originates from a cave within the El Abra Mountain giving this swordtail its common name of the El Abra swordtail. The El Abra swordtail is found along most of the length of the river but is most prolific nearest to the source. The population density decreases the further downriver you go and is not found where the Rio Choy joins the Rio Tampoan on its northern side.

The body colouration is greyish blue with a single bold zigzag midlateral line, in fully mature males the colour becomes more of an intense metallic blue and the midlateral line fades out. The males for X nigrensis have three size variations with the larger type male being the one most commonly found in the hobby. There are two main reasons that I can see for this, the first reason from a selfish point of view being that they are the better looking fish with the best colours. The second reason is a lot more understandable, in the wild the presence of larger type males is maintained due to them being bigger than the other males, this allows them the more prominent areas with which to attract the females. Swordtail females (according to some of the studies I have read) for their part are more amenable to mate with the larger males. However in the aquarium the smaller males mature more quickly and are therefore able to mate at a much younger age, this if left unchecked would create an aquarium population with only smaller type males, the larger type would disappear from the hobby.

This species is renowned for being difficult to maintain, they are highly susceptible to changes in water conditions particularly P.H. and with this in mind water changes should be frequent and small, a well planted aquarium with hard water and good filtration is undoubtedly the best environment to maintain them.

Xiphophorus multilineatus

Xiphophorus multilineatus is found in the Rio Coy and some parts of the Rio Tampoan. The Rio Coy is mainly formed from the waters of two springs, (the Arroyo Tambaque, and the Arroyo Oxitipa). Having a very similar description to the Rio Choy in being a fast flowing river with rocky habitats near the source and muddy/sandy substrates with dense vegetation in the slower areas. Xiphophorus multilineatus is found along the entire length of the river which is also a tributary to the Rio Tampoan but this time on the southern side.

Xiphophorus multilineatus is a similar looking species to Xiphophorus nigrensis and was often confused as such in early collections. In 1979 it was believed to be a separate population of X. nigrensis which I believe was responsible for the description being so much later than the initial collection. Xiphophorus multilineatus does have two major differences that separates it from X. nigrensis, the first being the stripes on the flanks of the males (this is where the name multilineatus comes from) and the second is the high back which forms on mature males somewhat similar to Xiphophorus birchmanni.

This species also has different size variations for males, the larger males develop a high back and vertical barring on the flanks. All males have a body colouring of pale metallic blue and a single bold zigzag midlateral line. As with the El Abra sword the larger type males are the ones most known within the hobby.

This is a shy species that requires a high level of vegetation in which to hide, although not as easily upset as X. nigrensis with water changes, the same routine is probably best followed. Water changes should therefore be frequent and small, the aquarium should be well planted aquarium with hard water and good filtration along with aeration.

Again this species is not as frequently seen at the auctions as it once was, these are lovely fish to keep and again also worth keeping.

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