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- Morphology Synopsis ( some meristic characters )
Total absolute length
Adult male : 16.0 to 121.8 mm
Adult female : 56.9 to 149.9 mm
Dorsal fin rays : / 10 ( 17 )
Caudal fin rays : / 26 ( 28 )
Scales on lateral line : 25 ( 30 )
Head length body length ratio ( male ) : 0,16 / 0,17
Head length body length ratio ( female ) : 0,18 / 0,20
- Habitat and Geographical distribution
Sailfin Molly wild populations are established
in a vast area, ranging from Cape Fear, North Carolina in the Atlantic
southern United States of America, down to Mexico, Vera Cruz State, in the
Golf of Mexico, occurring in river basins running to the Atlantic Ocean.
This is frequently considered as a temperate species, despite the fact that
it is found across a vast region ranging further south in to subtropical
In order to share a general idea about both limits of this species natural
geographic distribution, we can consider data from North Carolina and Vera
Cruz as an orientation.
North Carolina has in general a humid, subtropical climate especially at the
coastline where our attention is focused in.
Winters are short and mild, while summers are usually hot but temperatures
rarely go above 38ºC ( 100.4ºF ).
Mean annual temperature ranges 16.9ºC ( 62.4ºF ) by the seaside, however
differentiation in altitude and closeness to the ocean create significant
local variations inside the State territory.
Average January temperatures are around 9ºC ( 48.2ºF ), presenting extreme
limits between -2ºC ( 28.4ºF ) and 21ºC ( 69.8ºF ). Average July
temperatures can be around 27ºC ( 80.6ºF ), with lower limit around 19ºC (
66.2ºF ) and maximum limit near 37ºC ( 98.6ºF ).
Average annual precipitation at the coast line varying between 1120 and 1420
Especially for the summer period, North Carolina weather perform in response
to the Bermuda High pressure system, centred in the mid-Atlantic. Winds from
the southwest bring masses of hot humid air over the State.
Water temperature at Cape Fear River can show extremes stuck between 5.3ºC (
41.54ºF ) and 31.9ºC ( 89.42ºF ), reaching annual mean between 16.9ºC (
62.4ºF ) and 19.8ºC ( 67.6ºF ).
Please keep in mind that the local wild population of Poecilia latipinna
may rarely experience the lowest water temperature limits. In fact, has this
is a quite tolerant fish regarding salinity ( eurihalyne species ), it is
expectable that Sailfin Molly shoals may seek out refuge on the slightly
clement waters across the moth of the rivers or even in oceanic environments
near the coastline accessible right the way through tidal ditches and
Vera Cruz City is located precisely near the southern limit. Medium air
temperatures are around 20ºC ( 68ºF ) in January and 27ºC ( 80.6ºF ) in
Even so, this will never demonstrate in evidence the real local weather.
The hottest month in the region isn’t June but instead April, May or even
September, according to the place we are talking about.
Standard water temperatures can be 0.4ºC ( 32.7ºF ) higher in August than in
When the year’s peak hottest days take place in April, for instance, we are
talking about regions located at latitudes where the Sun is straight up at
that moment and raining season is still on the way.
Around May or so, as soon as the first seasonal heavy precipitations get
there, cloudy sky as well as rain “ freshness “ let the values get, somehow,
a bit downwards with reference to April. Even so, while maximum daily heat
fall a little, minimum lowers tender to rise due to overcast skies above at
By this same reason, in some other areas in the region, August or even
September can show the highest records, ( eventually caused by the clearest
skies after the heaviest rains ).
Down South, average annual temperatures can show a discrepancy of only 0.5ºC
( 0.9ºF ) between winter and summer ( January/July ).
Poecilia latipinna can be located from fresh water environments, to sea
water, including a wide range of brackish waters. Most populations show
however a preference for salinity limits below 1,007 ( 10,2 ppt ).
Common habitats are springs, lakes and ponds, rivers and streams, drainage
ditches, and salt marshes as well as most estuarine and sea line ponds or
lagoons, tidal ditches and brackish canals. Some populations invade marine
habitats, at least for short periods in seasonal basis. Others also search
for sea in order to find specific environment conditions seasonally.
This molly is found naturally close to shore, in the edge of streams or
ponds where it searches for shelter in shallow water usually near aquatic
vegetation banks, especially in quiet, often densely vegetated backwaters
rather than in open areas,.
In the North areas of its natural geographic distribution, Poecilia
latipinna share the same habitat with some small species, including
Gambusia holbrooki, Cyprinodon variegatus, Fundulus
confluentus and Lucania parva, which might mean that they all
need to look for refuge from larger predator fish species.
Adult animals can also be sporadically found in deeper waters around 50
centimetres, but usually avoid profundities of more than 1 metre.
Wild environment offers seasonally quite turbid waters, while they become
opaque and offers low visibility by the raining season.
In may locations pH values vary around 7,5 and 8,1.
temperature range :
62.6ºF ) - 27ºC ( 80,6ºF )
Tolerated limits :
between 7ºC ( 44.6ºF ) and 13ºC ( 55.4ºF ) plus 33ºC ( 91.4ºF ) and 35ºC
( 95ºF ) ( depending on population )
Survival limits :
between 4ºC ( 39.2ºF ) and 12ºC ( 53.6ºF ) plus 36ºC ( 96.8ºF ) and 39ºC
( 102.2ºF ) ( depending on population )
pH : 7 – 8.2
dH : 12º - 34º
Maximum salinity :
1,036 ( 87 ppt )
Temperature annual maintenance for this species in captivity (
suggestion ) :
one of this table lines report a different monthly period.
The temperature values are provided only as a reference for captivity
on this way your action can be considered reasonable, according with
the species known thermal exigencies.
is sometimes difficult, if not even impossible, to recreate in
aquarium the natural conditions, most favourable for the fish
biology. The most ideal situation was, if you could be able to
provide your fish a daily as well as a weekly temperature variation,
like in the wild.
For better understanding about perfect environment or to simulate
water temperature annual evolution according to natural habitat for
this species, please be so kind and have a look to
Savannah, Miami, New Orleans, Corpus Christi, Tampico and Veracruz
Wild water's temperatures ( all year round ) issue.
IV - Biology and ecology synopsis
All along this fish considerable geographical
distribution there is an extraordinary adult standard length variance in
both sexes. This phenomenon is a particular distinguish and occurs both
within and between populations. Males are however more prone to such
Predominantly among wild males it’s possible to find an amazing divergence
in maturation age, depending on the location, but in essence due to climate
In the State of Florida, United States of America, adult males can reach
from 16 to 103 mm Standard Length. Dorsal fins are also very variable,
reaching from 6 to 45 mm high possessing from 10 and 17 rays ( Snelson,
F.F., Jr. 1985 ).
Contrasting this species evident sexual dimorphism, some adult small males
30 mm long or less, don’t even show the typical secondary sexual
characteristics. They are quite similar to females and the only sexual
distinguish feature visible is the gonopodium.
Only males above 45 mm start to show conspicuously the phenotype typical
morphology, in particular showing those particular masculine traits that we
can testify on the common fish sold in pet shops. These larger ones start to
exhibit the traditional remarkable coloration and developed dorsal fins that
can reach up to 45 mm high, differentiate them perfectly from the opposite
sex and encouraging this way one of the species common names ( Snelson,
F.F., Jr. 1985 ).
While males do not occur in a close array of such 3 arbitrary classes, but
in a size and morphological continuum, the adult standard length and the
ratio between the before mentioned main groups are quite instable, so each
population composition contrast significantly.
At one extreme, males are always relatively small ( from 16 to 40 mm
standard length ) and larger males are absent. At the other extreme, the
population contains a full array of male sizes ( from 18 to 60 mm standard
length ), and undersized males are present only in small numbers, ( Snelson,
F.F., Jr. 1985 ). Precisely on these last populations, we can capture, in
particular during summer months, large exemplars resembling very much the
common aquarium form.
Possibly that characteristic size differences among populations may result
from some environmental parameters, social and genetic, that controls such
variability among males, ( Snelson, F.F., Jr. 1985 ).
Unfortunately domestic ( cultivated ) strains identified as Poecilia
latipinna are becoming recurrently a fusion of origins and ancient wild
proveniences, while many are, without any doubt, hybrids with other Mollies.
Sailfin Molly has managed to disperse over an impressive range occupying an
remarkable variety of habitats throughout its evolution.
It is still possible to find these fishes very well harmonized with both,
fresh and brackish waters, as well as in occasional sea penetrations from
some populations located on coastal areas. Such adaptability encourages
dispersal and new territories invasion.
In fact, this species show a wide tolerance to environmental factors and a
astonish adaptability, solving some challenges like to very low dissolved
Due to a physiognomic feature, these fish can in fact survive to very low
oxygen levels. On the limits Poecilia latipinna reduces consumption
rates and uses it flattened head, superior mouth position and special
designed lips, to draw water from a thin water surface film, where is still
possible to get some satisfactory levels of dissolved oxygen, on
environments where most fish would die from asphyxia.
Maybe in result of environmental as well as predatory pressure in the wild,
it isn’t very expectable to find large males as in captivity selecting
Even so, wild populations from several Poeciliid species, under strict close
contact with predators do show evidence for domain of larger individuals,
specially when compared with those other populations free from such stress,
( and this one is far from be an exception to the rule ).
Adult males shorter than 45 mm are also common in lesser populations or on
those regions where cold winters becomes more often noticeable. Immature
males born by the end of the breeding season will take longer to attain full
development and will grow until next spring when they reach sexual maturity.
The explication for this unequivocal size discrepancy lay on a simple
biological fact. Poeciliid males grow on an observable manner only until
they reach sexual maturity. As the red line achieve sexual maturity later,
some times weeks or even months after their dark line counterparts, growth
do not stops and they make the difference.
As many other large geographical distribution species we can become aware of
interesting local biological particularities.
Sexual selection may play an important role on such evidence as well as on
the species morphological variability.
Females fill more attracted and select males on the basis of higher dorsal
fin and more remarkable body coloration.
The counterpace is that a highlighted individual is also more evident to
predators due to more elaborate ornamentation.
The simple fact of a female’s let herself to remain in the presence of such
marked male during courtship, can put in danger her own life too, as they
both become conspicuous to near by predators.
Anyway, the male mating success it doesn’t depend merely on large fins and
bright colours or marks according to female’s predilection.
In the wild populations it is common to find more females than males, while
there is a relative symmetry in sex ratio among fry and young. The same may
happens also even in captivity when predators are not present.
While in natural environment these Mollies are omnivorous, with a
significant tendency for a vegetarian diet. They feed mostly on a diverse
sort of green matter ( predominately vegetal detritus, filamentous and
unicellular algae as well ), but also on almost all little live prey of
convenient size, like zoo benthos, zooplankton, aquatic invertebrates,
insects and their larvae, including mosquitoes on all living stages.
In captivity, domestic strains do adapt themselves to the usual fish keeping
The use of same foodstuff equivalent to other popular livebearer species is
a proper choice, without any particular complement or ration’s concern
besides some extra complement of green matter.
This is one of those species that accept flake industrial food with no
problem. Besides dry, fresh or frozen industrial type of nourishment,
vegetarian components must not be forgotten in the name of animal’s good
Occasional or frequent live preys do show some incredible impact on these
fish general health and body improvement.
Keep in mind that is however largely recommended to include, besides several
vegetal alternatives, brine shrimps, mosquito larvae, small aquatic
invertebrates and other usual live prey ( alive or frozen ).
You can add also milled row, fish or molluscs from about all kinds used on
human diet. Occasionally, once in a blue moon, you can use row meet from
cow, pork, rabbit or birds, without any fat at all.
Remember that there is always an identifiable difference, in growth rate and
fecundity, between fish communities of this species feed on natural
foodstuff and those who can simply get artificial alternatives.
Like other Poecilid fish from subtropical and temperate regions, this is not
a continuous breeding season kind species in a considerable area in the
As long as we move further north on its geographical distribution, more
often local populations face lower winter temperatures. In some areas that
means a breeding discontinuing period as water goes below 17ºC ( 62.6ºF ) to
14ºC ( 57.2ºF ), it depends a lot on which population we area talking about.
The State of Florida is considered a subtropical region, but even on its
southern limits the species had revealed to independent breeding seasons,
one between April and June and another one between August and October.
Generally a number of those males born in April can be ready to mate in
September or October. The adverse effect of attaining sexual maturity
earlier is that they will be usually undersized when compared with those
others who attain full maturity only between 11 and 13 months next spring.
As mentioned before, Poeciliid males on average stop growing on a noticeable
way after sexual maturity.
Nonetheless if we take in consideration the subtropical regions at the
southern limits of the species geographic distribution in Mexico, there is
no manifest interlude on the reproduction season and Poecilia latipinna
becomes a continuous breeding species.
The ideal temperature for gestation seems to be between 20ºC ( 68ºF ) and
26ºC ( 78.8ºF ).
Sailfin Molly female’s gestation period goes from 21 to 68 days. The time
between deliveries is rather related to water temperature, photo period,
salinity and nourishment.
Up to 29ºC ( 84.2ºF ) the gestation can take around 28 days, but above that
limit they can become longer and longer again. Above 32ºC ( 89.6ºF ),
complications and risks for both, mother and embryos, increase considerably.
Lab experiments had proven than salinity can also become a relevant factor
to take in consideration. The discrepancy between fresh water and several
other salinities could represent up to 4 days in gestation limits, although
all other variables were constant, ( Kumaraguru Vasagam et al., 2005 ).
Salinity is also a key factor on reproduction success, newborn size, and fry
According to the same source, the largest number of babies for delivery took
place at 25% salinity ( 1,018 ). On the other hand the lower numbers are
achieve both in fresh and sea water - 35% salinity ( 1,026 ).
Another important piece of information, as consequence from this lab
experiment, is that better fry growing rates have took place at 10% salinity
( 1,007 ), ( Kumaraguru Vasagam et al., 2005 ).
The initial conception or pregnant females submitted to long term aguish,
stress or anxiety, may have irregular broods, which can go up to 90 days or
Full developed larger females can deliver 200 newborn or slightly more.
Cannibalistic conduct in captivity is infrequent, but it may happen in small
tanks or when are present famine adults as well as when fish are submitted
to a poor dietary.
Fertilization takes place about a week after delivery.
The quite popular use of “ maternity “ cages is one of the most noticeable
sources of stress, commonly associated with gestation problems. Females
subjected to such experience in cages will face permanent agony and
suffering. They can refuse to give birth for long periods.
These unnecessary long pregnancies are very often related to health
complications that result on problematical deliveries, spontaneous abortions
and high rates of fatalities in newborn fish.
A successful mating can originate as far as 8 consecutive broods. Females
can store viable sperm for periods up to 2 years.
Feeding newborn and fry will be no particular problem at all. This species
will fallow usual needs from other members of Poeciliinae sub-family.
The newborn are relatively large. They can measure from 9 to 12 mm at birth.
Less than an hour after birth they accept small live prey as aquatic
invertebrates of the proper size to their moth, or any other artificial
common food for baby fish.
V - Complementary notes
This species can, in some cases, behave in a
hostile way against other fish in captivity, but more frequently such
belligerence is oriented towards other Sailfil Molly rival males and not to
other tank mates. This is particularly true in smaller tanks, where the
vital space isn’t enough for the species biology requirements. Despite of
that this is a proper option for almost any community tank.
In fact, these expected male disputes don’t harm other fish around and
generally will not result in injuries to the antagonists itself.
Keeping this species in outdoors garden ponds, particularly on brackish
water, will be an extremely favourable option. An evident return will become
clear as time goes by in terms of growth and general health, as well as on
male’s dorsal fin enlargement.
Back in the wild there are a number of predators feeding on this Molly.
Aquatic insect larvae ( attack only fry and young ), other fish species,
reptiles, amphibious, mammals and water birds are among usual pisicivorous.
Partially for this reason Sailfin Molly is found frequently in stagnant
organic enriched waters, with high primary productivity ( eutrophic ), or
locations with exuberant aquatic vegetation were the fish look for some
protection. There are only a few other fish species who can compete for
resources an live on such environment.
It is also a live indicator for pollution and water contamination, as it can
survive in low dissolved oxygen concentrations, being one of the last
species to withdraw from dreadful conditions for the aquatic live.
VI - Threats, protection
and present status
Due to its
broad geographical distribution, wild Poecilia latipinna populations
are only familiar with human environmental pressure in some populated
regions, essentially in United States of America.
lack of data concerning the recent live history of populations in North
Carolina, for instance, are not helping much the knowledge about the
present and a foreseen fish status.
Sailfin Molly is a species abundant in
line lakes, ponds, salt marshes as well as in most estuaries, brackish
water lagoons, which means that on the northern regions of its natural
geographical distribution is possible that the species is under pressure
by lost of habitat when these areas are altered for building purpose or
vast natural distribution, auspiciously many populations can stay free
from human pressure; most of all those located in remote wild regions.
In the near future a situation of intense threatening upon this species
isn’t predictable. Nevertheless, in some restricted areas there are,
right now, situations where there are already populations under harass,
suffering from a number of varied risk extent.
release of domestic ( cultivated ) strains in the wild can become a
genetic threat to the local fish.
further knowledge or information about this please check
Livebearer Cyprinodontiformes in the IUCN Red List of Threatened Species.
Other topics available about this species
cited ( references ) :
Aspbury, A.S., and C.R.
Gabor. 2004. Differential sperm priming by male sailfin mollies (
Poecilia latipinna ): Effects of female and male size.
Brown, W.H. 1953. Introduced species in the Guadalupe River basin.
Texas Journal of Science, 5:245-251.
Burgess, G.H. 1980. Poecilia latipinna (Lesueur), Sailfin
molly. P. 549 in D.S. Lee, et al.
Atlas of North American Freshwater Fishes.
N. C. State Mus. Nat. Hist., Raleigh, i-r+854 pp.
Cook, F.A. 1959. Freshwater fishes
Mississippi Game and Fish Commission,
Jackson. 239 pp.
Edwards, R.J., and S.
Contreras-Balderas. 1991. Historical changes in the Ichthyofauna of
the Lower Rio Grande ( Rio Bravo del Norte ), Texas and Mexico.
The Southwestern Naturalist 36(2): 201-212.
Evermann, B.W. 1899. Report on
investigations by the U.S. Fish Commission in Mississippi, Louisiana,
and Texas, in 1897.
Rept. U.S. Fish Comm. 24:287-310.
Farr, J.A., and J. Travis.
1986. Fertility advertisement by female sailfin mollies, Poecilia
latipinna ( Pisces: Poeciliidae ).
Franklin F. Snelson, Jr., 1985. Size
and morphological variation in males of the sailfin molly, Poecilia
Environmental Biology of Fishes Vol. 13,
No. 1, 1985, pp. 35-17.
Harrington, R.W., Jr., and E. S.
Harrington. 1961. Food selection among fishes invading a high
subtropical salt marsh: from onset of flooding through the progress of a
Hellier, T.R., Jr., 1967. The fishes
of the Santa Fe River system.
Bull. Fla. State Mus. Biol. Ser. 2(1):1-46.
Hubbs, C., R.J. Edwards, and G.P.
Garrett. 1991. An annotated checklist to the freshwater fishes of
Texas, with keys to identification of species.
The Texas Journal of Science, Supplement,
Hunt, B.P. 1953. Food relationships
between Florida spotted gar and other organisms in the Tamiami Canal,
Dade Country, Florida.
Trans. Amer. Fish. Soc. 82(1952):12-33.
K.P. Kumaraguru vasagam, S.
Rajagopal, T. Balasubramanian, 2005. Effect of Salinity on
gestation period, Fry Production, and Growth Performance of the Sailfin
Molly ( Poecilia Latipinna, Lesueur ) in Captivity.
The Israeli Journal of Aquaculture –
Bamidgeh 57(3), 2005, 191-196.
Lesueur, C.A. 1821. Description of a
new genus, and of several new species of fresh water fish, indigenous to
the United States.
J. Acad. Nat. Sci. Phil. 2:2-8.
Lewis, W.M., Jr., 1970.
Morphological adaptations of cyprinodontids for inhabiting oxygen
Parenti, L.R. and M. Rauchenberger. 1989. Systematic
overview of the poeciliines, pp. 3-12.
Ecology and evolution of livebearing fishes
(Poeciliidae). Prentice Hall, Englewood Cliffs, N.J. 453 pp.
Peterson, M.S. 1990. Hypoxia-induces
physiological changes in mangrove swamp fishes: sheepshead minnow
Cyprinodon variegatus Lacepede and sailfin molly Poecilia
Comp. Biochem. Physiol. 97A(1):17-21.
Ross, S.T. 2001. The Inland Fishes
University Press of Mississippi. 624 pp.
Snelson, F.F., Jr., 1982.
Indeterminate growth in males of the sailfin molly, Poecilia
Snelson, F.F., Jr., 1984. Seasonal
maturation and growth of males in a natural population of Poecilia
Snelson, F.F., Jr. 1985. Size and
morphological variation in males of the sailfin molly, Poecilia
Env. Biol. Fish. 13(1):35-47.
Snelson, F. F., Jr., J. D. Wetherington,
and H. L. Large. 1986. The relationship between interbrood
interval and yolk loading in a generalized poeciliid fish, Poecilia
Trexler, J. C. 1985. Variation in
the degree of viviparity in the sailfin molly Poecilia latipinna.
Warren, M. L. Jr., B. M. Burr, S. J.
Walsh, H.L. Bart Jr., R. C. Cashner, D. A. Etnier, B. J. Freeman, B. R.
Kuhajda, R. L. Mayden, H. W. Robison, S.T. Ross, and W. C.
Starnes. 2000. Diversity, distribution and conservation status of
the native freshwater fishes of the southern United States.
Winemiller, K.O., F.P. Gelwick, T.H.
Bonner, S. Zueg, and C. Williams. 2004. Response of oxbow
lake biota to hydrologic exchanges with the Brazos River channel. Report
to the Texas Water Development Board. 59 pp.
Other topics available about this species :
Female mating preferences for male morphological traits used in species
and mate recognition in the Mexican sailfin mollies, Poecilia velifera
and P. petenensis.
Behavioral Ecology, 19:463-474, 2008
Kozak, H. L., Cirino, L. A. and Ptacek, M.
Geographical variation of genetic and phenotypic traits in the Mexican
sailfin mollies, Poecilia velifera and P. petenensis.
Molecular Ecology, 17:2219-2233, 2008.
Hankison, S. J. and Ptacek, M. B.
Morphological divergence within and between the Mexican sailfin mollies,
Poecilia velifera and P. petenensis.
Journal of Fish Biology, 68:1610-1630,
Hankison, S. J., Childress, M. J.,
Schmitter-Soto, J. J., and Ptacek, M. B.
Within and between species variation in male mating behaviors in the
Mexican sailfin mollies Poecilia velifera and P. petenensis.
Ethology, 113:802-812, 2007.
Hankison, S. J., and Ptacek, M.B.