Cyprinodontiformes vivíparos e ovovivíparos

Livebearer Cyprinodontiformes

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Species > Species profile > Poecilia reticulata

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I - Morphology Synopsis ( some meristic characters )

Total absolute lenght

Adult male : 15.5 a 34.7 mm (*)

Adult female : 28.1 a 58.9 mm (*)

Dorsal fin rays : / 6 ( 7 )

Caudal fin rays : / 12 ( 14 )

Scales on lateral line : 26 ( 27 )

Head lenght body lenght ratio ( male ) : 0,20 / 0,21

Head lenght body lenght ratio ( female ) : 0,19

* As a general rule, wild animals are smaller than most domestic strains raised by atrophic selection.

More often than not, adult males captured in nature vary from 15.5 mm to 29.9 mm while females from same populations can alternate between 28.1 mm and 49.9 mm in total length.

Despite that, fancy cultivated lineages can some times go even further than above mentioned values for total absolute length.

 
You can find more pictures about these species availabe at the photo gallery.

II - Habitat and Geographical distribution

Today the Guppy is acclimated in a vast tropical area virtually around the planted, in particular where water temperatures are stuck between 18ºC ( 64.4ºF ) and 32ºC ( 89.6ºF ).

No so long ago, before a wide-ranging use of this fish as biologic instrument to mosquito control, the original wild distribution was quite less important.

Before this intended man dissemination due to a supposed high effectiveness to destroy malaria vector mosquito larvae, Poecilia reticulata was limited to a large region ranging from Macaraibo lake in Northern Venezuela to the hydrographical basin of Solimões River in Brazil, including a number of coastal countries like both Guyanas and Suriname as well as some areas in several States of Northern Brazil ( Roraima, Pará e Amapá ).

Some Caribbean Sea islands close to South America are also considered as part of the original geographical distribution. In most sources we can find that small islands North of Venezuela like Aruba, Curacao, Bonaire, Margarita, La tortuga ( ? ), La Branquilla ( ? ), Los Testigos ( ? ), Coche ( ? ), Cubagua ( ? ) as well as some others in lower Caribbean like Trinidad and Tobago, Granada Saint Vicente and Santa Lucia are also the home land of this species. Barbados, also considered inside the original range, is out of it according with several scientific sources.

As result of a widespread dissemination by a vast global belt on the tropical regions ( more or less near the equatorial area ), there are some official reports of adverse ecological impacts in some countries as well as information with reference to low or neutral impact on the mosquito after the introduction.

As it can read ahead, Trinidad and Tobago is one of the most representative locations for this species for science and for the hobby.

This country is in fact an archipelago located in the southern Caribbean Sea, relatively near the continent next to the northeast coastal region of Venezuela and not far from one of the most important hydrographical basins of South America, the Orinoco River.

Many aquaria hobbyists still believe that a considerable genetic legacy in most of the domestic strains is made of Trinidad originated ancestors, as regard for many historical sources.

These islands climate is tropical, with a high relative humidity. The islands are located outside the main hurricane sector, but sporadically are struck by these disastrous tropical storms.

As we are referring to islands, the maximum temperatures are never very high, 32ºC ( 89.6ºF ), and minimum temperatures never go too low, 19ºC ( 66.2ºF ). The climate along the coast is tempered by sea breezes but temperatures vary significantly between day and night in particular inland and on the top of the mountains.

The coolest months are January and February.

Average minimum temperature is about 20°C ( 68ºF ), showing values between 16ºC ( 60.8ºF ) and 27ºC ( 80.6ºF ) on the coldest period of the day in this season.

Average maximum temperature during these winter months is around 28ºC ( 82.4ºF ), with variations between 24ºC ( 75.2ºF ) and 32ºC ( 89.6ºF ) at the hottest period of the day.

The warmest months are April, May, and October.

Average minimum temperature is about 24°C ( 75.2ºF ), showing values between 19ºC ( 66.2ºF ) and 28ºC ( 82.4ºF ) on the coldest period of the day in this season.

Average maximum temperature during these winter months is around 31ºC ( 87.8ºF ), with variations between 27ºC ( 80.6ºF ) and 35ºC ( 95.0ºF ) at the hottest period of the day.

Variations are remarkable on a daily basis but, day to night differences, under no circumstances break out the supra mentioned limit values.

There is a main dry season from January to May and a lesser dry season ( “ Petite Carême “ ) in September and October.

Rainy season is from June to August and in November/December again.

As mentioned before, we cannot keep an accurate notion about thermal biological exigencies of a fish, though simply taking in consideration the historical data regarding air temperatures of a single specific locality. The best we can find from that practice is to have an estimated idea of what kind of environment that a particular population is living on.

It isn’t a purpose neither an objective of this modest work to deal with some concepts like a rigorous analysis about air and water thermodynamics as well as mutual influence. Apply such concepts to our data collection about air temperature from Trinidad is than out of question.

Taking into consideration the insignificant data that was possible to collect about the island temperature records it is possible to conclude at least two basic ground rules.

In first place, populations from this part of the world have been submitted to daily thermal variations along their long evolution process. That’s why it’s important to keep in mind the importance of night and day variations and how harmful constant temperatures can become, above all if these invariable conditions remain for months long.

Secondly, remember that this species doesn’t stand large amplitude. Besides a certain resistance found in specific and rare populations, Guppies in most cases doesn’t thrive for long periods below 17ºC ( 62.6ºF ) although it can stay alive for several days at 15ºC ( 59.0ºF ) and, in some exceptional very rare cases, even a little bit lower, according to unconfirmed reports from hobbyists.

In the wild, this species is found usually in rivers, streams, brooks, rivulets, channels, lakes, marshes, pools, ponds, poodles, swamps, coastal lagoons, but also in transition zones between fresh water and the sea like estuaries and mangrove swamps.

While struggling for survival, Poecilia reticulata occupies sometimes isolated low deep spots and water bodies. Precisely on these shallow environments they are save from many of the main predators below the surface and can proliferate quite well. However, a lot of these safe havens are, now and then, submerged by floods and inundation during the raining season, becoming part of a larger water body for some time.

Populations located in larger rivers or in some lakes, usually search fro protection in the edge of shore, looking for areas with dense sub aquatic vegetation, or predominantly at the backwater neighbourhood.

Another typical preference in terms of habitat is no doubt shallow waters, especially when the bottom doesn’t go further than 1 meter deep. In some places we can find colonies living in brooks, streams, rivulets or small pool and poodles with only about 10 centimetres deep or even less at least for the period of the drought season. This strategy keeps absent water predators of larger size but becomes a challenge to face the danger coming from above water surface.

Several and diverse sort of waters can house Guppies, not only at original ecosystems but in introduced new environments, as well. Very well adapted populations can be identified from clear transparent waters in mountain creeks, to opaque turbid waters of lowland rivers and lakes. In some typically clear water locations is however expectable that, during rainy season or under stormy conditions, the floods and by strong torrent events, conditions change to very murky conditions. In other environments, at some stages, conditions are favourable to micro algae boom, which alter clearness to exceptionally low levels of visibility under water.

Some introduced stable populations are common at high salinity biomes, at mangrove swamp areas as well as river mouth habitat ( estuarine ). Marine environment rarely offer conditions to this species, particularly where fish can’t find protection from predators, due to strong running waters or if facing sea undulation.

Owing to the species dispersal it’s possible to find now some established populations where in theory these fish should not be thriving. This is the case of some relatively polluted waters as well as swampy acidic environments ( pH 6,1 and sometimes even less ).

The adaptability of Poecilia reticulata is tremendous. This resistant, successful and powerful colonizer of new habitats becomes extremely adjustable to the latest defy as well as to new demands. The major vulnerability is no doubt temperature limits.

Nevertheless, please respect the biological and environmental demands as best as possible according to known ideal values. It’s important to avoid expose these fish to extreme conditions, particularly the fancy domestic strains due to their expectable lower resistance when compared with the wild ones.

III - Physical-chemistry parameters

Ideal temperature range : 18ºC ( 64.4ºF ) - 28ºC ( 82.4ºF ), 23.5ºC ( 74.3ºF ) seams to be the universally accepted most favourable value off all

Tolerated limits : 16.5ºC ( 61.7ºF ) e 33ºC ( 91.4ºF )

Survival limits : 12ºC ( 53.6ºF ) a 36ºC ( 96.8ºC )

Ideal pH : 7,2 – 7,4 ( tolerate from 6,6 to 8,2 )

Ideal dH : 8º – 19º ( tolerate from 4º to 30º )

Maximum salinity : 1,042 (*) ( 42,4 ppt )

 
(*) Please keep in mind that this is in fact an eurihaline species, or by other words, it can stand a wide range of salinity and salinity fluctuations, ( and by this reason be sometimes find at sea waters as well as hyper-saline environments ), it occurs frequently in brackish waters. Despite that, remember always that we are in face of a freshwater fish long evolution and by that reason it’s not proper to keep permanently in the marine aquarium.

 
Temperature annual maintenance for this species in captivity ( suggestion ) :
 

Most highly regarded breeders of fancy Guppy strains as well as most clubs usually don’t specify that these temperatures are in fact appropriated merely for the average targets related to domestic strains selection. In this manner, aquaria hobbyists can, above all, get from their stocks faster growing and breeding pairs durability.

Anyhow, it is important to have in consideration that such thermal procedure doesn’t satisfy the basic fish needs of proper caring, concerning in particular the species evolution and nature background.

On the other hand, to accomplish such biological demands in a decorative thank, placed inside a modern apartment, it can reveals to be quite easier said than done, mostly because of human comfort requirements.

 

IV - Biology and ecology synopsis

Common Guppy represents one of the most evident examples of variability and polymorphism within a single species.

Every so often it is possible to find, even inside a particular water body, dissimilar groups with different adult sizes, distinctive body colours and patterns or other particularities. This multiplicity is so regular that can even take place in a single hydrographical basin or restrict region.

Male body colours and drawings are typical from each area. They are the combined end result from environment and predator’s action, among other causes.

Apart from morphologic distinguishing features, it is even possible to stumble on behaviour idiosyncratic differences between populations.

There are places where these fish remain incessantly in dense shoals, while not so far upstream, they attract our attention by foraging independently with the group spread by a rather wide area.

Males captured in the wild are polychromatic. They present a quite varied assortment of areas, spots, marks and blots, from several colours in flanks as well in several fins.

More frequent tones are bright red, yellow, blue, green and white, together with several black spots, lines and even small or large body regions.

A number of scientific papers have reached to evident conclusions and a quantity of quite clear grounds to give good reasons for the evolution in to such prosperous chromatic assortment as well as plasticity in a population basis. Also morphologic somehow common divergences and uniqueness of some wild groups can be explained under the same theory.

Guppies living under higher predation pressure arrive at sexual maturity earlier and attain less significant adult sizes. They also produce smaller newborn and more embryos by brood, besides fecundity differences when compared with lower predation pressure populations ( David N. Reznick et al, 1996 ).

Diversity is at such level within on this species and is so apparent, that in some cases we can find even some rudimentary speciation processes.

The Endler’s Guppy or Cumaná Guppy was in the centre of an interesting and ardent topic of discussion between scientists and hobbyists during decades.

Although anatomic differentiation is not very clear and too evident, ( at least taking in consideration the above mentioned variability and polymorphism within this single species ), something new was already possible to speculate on the first animals captured in Cumaná, Venezuela, by 1935 and later introduced at aquaria hobby after 1975, from some exemplars of the living stock bring by Professor Jonh A. Endler.

It is also extraordinary that this fish have not received a proper scientific classification, if not since 1935, at least from 1975 to 2005.

Examining osteological morphology of both ( Endler's and common Guppy ), consistent differences aren’t easily achievable through body characters and any DNA studies have never been revealed to the hobbyists.

Several experts claim they found something that might differentiate them with perhaps enough to characterize Endler’s as an independent Poecilia reticulata strain, Alexander and Brenden, ( 2004 ).

This fascinating discuss would finally come in to an end by 2005.

Throughout all the information we could reach, during roughly 30 years, every one of the exploration enterprises to locate this second group have failed, but surprisingly in July 2002 two Europeans - Fred. N. Poeser and Michael Kempkes – discover several wild populations at Laguna Campoma, Laguna Buena Vista ( Cariaco ), Paria Peninsula and Carúpano region at Sucre State, Venezuela. Several populations with common characteristics would be classified by science as a new species Poecilia wingei or Campoma Guppy, ( Poeser, Kempkes and Isbrücker,  2005 ).

Besides a vast geographical distribution and some population’s long isolation, two other main reasons can give explanation for such diversification incidences as well as some hypothetical speciation progression in some Poecilia reticulata restrict groups.

By stimulation of sexual selection usually secondary sexual characters in males are the most evident to call female attention. The problem is that the same ingredients used with the intention of catch the attention of the opposite sex, like bright and conspicuous body colours, also work very well to catch the attention of hungry predators around.

Under this dilemma and dichotomy, many morphologic adaptations have result in an evolution course between sexual competitions as well as by predators under and above the water surface.

Those who already had the chance of observe wild Guppies in natural environment, especially at the original distribution waters, can eventually become aware of so many familiar traces that domestic fancy strains become not as much of fantastic and prodigious work after all. The number of fancy strains patterns find on wild animals is notable. It becomes quite easy to anticipate the ancestors for certain captivity lineages.

Bright as well as many colours and high developed fins as consequence of artificial antropic selection are so attractive to human aesthetic conceptualization, that a huge profitable market was born showing an impressive financial vigour. The fancy Guppy strains magnetism as well as care for is so important world wide, that several clubs and organizations of hobby breeders arise last century and are growing even today.

Yet, these man made “ beauties “ are the opposite and wrong way in terms of natural evolution. For millions of years, wild fish were “ tailored “ by predators and by the environment it self in Trinidad and Tobago, as well in original distribution in South America.

Natural predators are so many that is impossible to list them all, but some are easy to find in different sort of sources.

Some fish like Airus spp. Aequidens pulcher, Astyanax bimaculatus, Cichlassoma spp., Crenicichla alta, Crenicichla saxatilis, Dormitator maculates, Hoplerythrinus unitaeniatus, Hoplias malabaricus, Rhamdia sebae, Rivulus hartii, and Symbranchus marmuratus are easy to identify in the literature as well as in scientific papers.

Also very active underwater natural predators are invertebrates like freshwater shrimps Macrobrachium sp and aquatic insect larvae.

From above surface the danger is represented in form of fishing bats ( Noctilio spp. ) and fishing birds from genus Ceryle, Chloroceryle, Pitangus, etc.

Not all of these species are present in the same bioma or region.

On the other hand, the kind of pressure is quite assorted ( just adult prey/no more than fry, all year round/seasonally, above all males/mainly females, at surface/in deeper waters, and so on ). Killing effectiveness also show a discrepancy, ( infallible/low efficiency, very deadly/less lethal, and so forth ).

Some of the above cases in point are very common in scientific articles as they are animals from the Trinidad ecosystem. However, to understand how it works it is important to have in mind that in the vast natural region of ancient geographical distribution the number of different predators are an remarkable assortment, ( not to mention in the vast new areas of man made introduction ).

The interaction with hostile animals is fascinating as it allows us to discover exclusive social and reproductive behaviours as well as demography dissimilarity between populations. In addition to the environment specificity, the particular composition and number of predators present in an explicit location, pay an important role on this.

Populations facing a low or inexistent predation pressure can be observed foraging even at night.

While suffering predation pressure, these fish have a propensity to search for refuge in dense aquatic vegetation and don’t feed in the dark, so a number of negative consequences regarding in particular growth as well as breeding can be acknowledged, ( Douglas F. Fraser et al., 2004 ).

Adult size deep dissimilarity and sexual maturation, particularly among males, is also described as highly divergent in wild fish from different populations.

Contrasting with what we can testify in fancy strains, the original ancestry, as those fish locate currently in nature can actually show a great size assortment.

Gradual minor males in aquarium born Guppies can correspond to some kind of spontaneous effect regarding endogamy consequences. Unlike domestic raised ones, adult size diversity is the end result from environmental pressure and specific responses to survival need.

As many other related species, unlike females is not often a male demonstrate some perceptible and evident body development very short after sexual maturity, so the process of maturation will be restrictive to final length attained by males. This can explain such variability and divergence between wild and fancy animals in particular.

In continuous reproduction season species like this one, as soon and longer individuals can breed as better, especially from population facing constant demographic pressure from predation or outstanding adverse ecological occurrences point of view.

Larger males are also valuable especially if taking in consideration male to male mating competition and female’s preference.

Populations under a lesser amount of stress can hold larger males. They also take advantage from more favourable conditions that allow slower growing rates, later maturation, longer longevity and not as much newborn by each single birth.

In many tropical regions, very remarkable environment sudden changes can be expected, during raining season. Usual floods as well as natural catastrophes don’t let other alternative than forced drifting migration movements, either to search for acceptable continued existence conditions as to carry on after devastation.

Although classified above as an uninterrupted reproduction species, is precisely on the heavy rain period of the year, when reflective changes fall down intensely on ordinary conditions, that births become clearly more restricted and some populations show some breeding seasonality.

Female’s deliveries attenuation can take place around May/June or November/December in natural regions of Trinidad and Northern Venezuela, particularly in some years, it all depending on weather particular conditions.

In terms of reproduction, male’s can implement two primary behavioural strategies.

Some perform a ritual courtship prior to copulation, while others usually opt by sneaky mating forcing females by surprise.

During courtship it is possible to observe a certain ritual of movements to enhance male’s colours. Performing like this they can get two possible reactions from females. Receptive ones will accept copula ( insemination ), not receptive ones will turn in to a different direction and go away fast from the despised flirter.

Sexual selection is particularly associated with courtship.

Contrasting with this sexual conduct, it’s also quite regular and widespread another demeanour.

Some males approach surreptitiously from behind and try a sneaky mating, getting females by surprise.

With rare exceptions, the reaction is quite clear… escapee and a fast retreat performed by the attacked one.

It is possible that this last sexual behaviour can be less effective than courtship, but it is quite frequent and allows abundant successful inseminations.

In captivity sneaky mating is more often observed and is more recurrent than courtship, but in nature the balance between these two sexual behaviours is intimate related with predatory pressure as well as other environmental factors.

Multipaternity is more often in the presence of usual sneaky mating, while when a single male can assure the progeny of several newborn in a single delivery is commonly related to ritual mating.

Gestation in optimal conditions can take from 22 to 27 days according to personal observations in natural habitat.

In aquarium sometimes this period is frequently superior, in particular when pregnant females are submitted to long term aguish, stress or anxiety.

The quite popular use of maternity cages is one of the most noticeable sources of stress, commonly associated with gestation problems.

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.

In good conditions this species will become highly prolific.

A single delivery can produce from 6 to 8 babyish in inexperienced young mothers to 60 or even more in fully grown ones under most favourable breeding situation.

The number of offspring and their rate of development can also be correlated to specific conditions. The restrictive factors aren’t only under direct influence from environmental circumstances but from other particular reasons.

In the presence of predators, the number of births for each delivery increase to face demographic pressure as well to assure the group survival.

Cannibalism is something to consider as expected, above all in little aquariums or in the presence of unbalanced diet composition and unnourished adults.

Guppies observed in natural waters, are find in swallow waters close to shore, placed in several groups composed by several hundred adults and a equally abundant number of immature fish in several development stages.

According to the kind of predators they need to face and the profusion of in close proximity shelter, these populations can be seen in dense solid shoals or, quite the opposite, in extensively disperse groups, disseminated by the available space, either near by the surface either foraging on the bottom to about 1 meter deep, all at once.

In larger groups, when less submitted to predation, it’s possible to watch a frequent antagonism between males. Under these circumstances, courtship is quite common and disputes are more evident.

When adults are prey, males are less highlighted, body colours are paler and sneaky mating is almost the rule.

If allowed, females are on average more attracted to males of their own original population or strain with respect to male colour-pattern elements, body shape and size, and overall colour and brightness contrast.

Has we can see in numerous scientific papers like in “ Geographic Variation in Female Preferences for Male Traits in Poecilia reticulata “, sexual selection on wild Guppies collected in 11 different location in Trinidad, are quite expressive concerning this idea ( Endler & Houde, 1995 ).

Conversely, this evolutionary pattern brings a few survival questions.

To females, bright multi-coloured males are no doubt favourites and these have a propensity to become more successful breeders than inconspicuous ones. On the other hand, more vibrant fish are no doubt easy identified by predators in any circumstance.

Resulting from this fact, in many populations, whenever a female needs to avoid males and mating, simply search for open waters near by. Eventual suitors will remain near by next protection of dense vegetation or shallow waters to prepare a straightforward escape in case of predator’s attack.

This isn’t achievable in the preponderance of captivity environments, so aquarium born females are typically unable to avoid mate pressure, ( even when that is essential to her wellbeing or even health ). The exception to this rule is lakes and garden pools. If large fish or even predator ones are also included, the natural behaviour can also become perceptible on domesticated individuals under the above mentioned circumstances.

Wild Guppies feed in particular on zooplankton, small insects, aquatic insect larvae, micro-algae and vegetal detritus.

The percentage of these diet components are highly related to local availability and fluctuate according to each region particularity, ecosystem idiosyncrasy, and seasonal ease of access.

In some parts, fish can benefit from assorted nourishment all year round, in other places they must consume some particular foodstuff according to a specific seasonal ease of access.

Under a so vast geographical distribution, particularly after man made introductions all over the world in tropical waters, nowadays many populations can afford from quite out of the ordinary sustenance. Even so, some research scientific work with Poecilia reticulata in natural waters can lead us to interesting conclusions.

Seasonal fluctuations take place especially where climate annual variation is greater.  In any case, even in classically equatorial climates, presenting small thermal annual amplitude, diet can show drift in some particular periods. The abundance of some resources can benefit local population’s sustenance and fish take advantage from unexpected resources sudden boom.

During raining season, floods usually reduce live prey as insect larvae. The overflow as well as stronger running waters disperses live organisms for vaster areas in inundated land, besides lower visibility and turbidity as direct cause from turbulence.

Micro-algae can represent around 75% of matter find at gut and digestive system. Insects and insect larvae are also very important constituent of digestive assemble, ( particularly Dipterans, Ephemeropterans e Trichopterans ).

In several scientific papers looking for an assessment of Guppy real value and efficacy as biological agent against vector of several diseases virus transmission mosquitoes, the digestive system substance from a number of captured animals is used as sampling.

Examined exemplars from Venezuelan waters ( Laguna de Urao, Mérida ), have show gastrointestinal contents with a varied composition. 62% of the observed fish had insect larvae mixed with other less significant nourishments but 33% of them could effectively reveal only mosquito larvae and pupas.

In reference to this same study, some other contents could be discover inside the digestive system of  Poecilia reticulata : algae, fish ( fry ), quironomids, coleopterans, copepods, dipterous, formicideous, odonates, hemipterous, larvae, pupas and detritus ( Rojas et al., 2005 ).

Captivity nourishment presents no problem.

In open air lakes and garden ponds, the typical “ green water “ caused by micro-algae in some of these environments is a fine component of all stages diet. Some other algae find covering the submerged walls are also an excellent source of food.

Guppies will eat greedily almost all usual nourishment for pet fish. They tolerate very well dry commercial flakes, fresh, frozen and live prey.

Some domestic fish recipes and formulas are also very popular and show good results with this species.

An adequate food diet fallows the same consideration for other common ovoviviparous. Nonetheless, is very important to remember always that the vegetarian needs should never be forgotten, including some industrial foods based on spirulina algae.

Besides flake rations, it’s essential to provide brine shrimps, mosquito larvae, blood worms, tubifex, daphnia, ( all sliced or selected with the proper size to these fish mouth ).

You can add also milled row fish or molluscs from about all kinds used on human diet.

Feeding newborn and fry will be no particular problem at all. They accept very well powdered flake food and industrial fry food suitable for Poeciliids as well as fine particles of adult nourishment. Nevertheless it is vital to feed them, as often as possible, with live prey like brine shrimp nauplii, micro-worms and infusorians.

Remember however that this is a fast metabolic fish. Particularly under higher temperatures feeding your Guppies must fallow the rule of several small doses a day depending on your accessible free time, ( between 3 and 8 times only during light period ).

Each prescribed amount of food must be only enough to be consumed in a few minutes without letting remnants at all.

As wide-ranging and diverse the nourishment will be, as best the reflex you can expect on fish healthiness as well as in physical condition and growth.

Due to a fast metabolic system sooner or later partial water exchanges are imperative, independently of the filtering effectiveness. Especially in small water capacity containers or in long setups, frequent and partial water changes must take place in order to combat extremely harmful bacterial effects that can origin massive sudden casualties.

A little tank of 40 litres working for about 5 months as well as another one of 200 litres working continuously for the past 11 months, they both need something around a weekly 20% partial water change.

These same two tanks a few months later, ( if not dismounted and reassembled again meanwhile ), must receive at least as much as the double partial water changes weekly, ( of about 25% ), and so forth.

Aquarium sanitation is extremely significant. The unwanted debris is the breeding ground for disease agents, which are in most instances responsible for several fish infirmities.

In captivity these fish can survive for around one and half years but some individuals can go further that limit as long as almost two times.

V - Complementary notes

This species was described for the first time in 1859 by the German Ichthyologist Wilhem C. H. Peters, based in a sample of specimens collected in 1856 at Guaíre River ( Venezuela ). As a remarkable fact, this scientist would give to this new fish the same scientific designation that we use presently, but this wouldn’t happen to become uninterrupted, as we can see further ahead.

The popular Guppy name remains after an eminent personality rediscover it in Trinidad’s waters around 1866.

Robert John Lechmere Guppy, ( born August 15, 1836 in London; deceased August 5, 1916 in San Fernando – Trinidad and Tobago ), was an British born naturalist.

Regarding the naming of this fish, Lechmere Guppy's daughter, Enid Fraser, was quoted in The Aquarium, Vol. XIV nº 7, November, 1945, as writing the following :

« (…) chief credit for the name should go to my father, the late Dr. Robert John Lechmere Guppy who, although a conchologist and geologist was the first to discover the small livebearer here [ Trinidad ] and was rather intrigued by its appearance.

He sent specimens to London for cataloguing and scientific description by the then Keeper ( Curator ) of Zoology of the British Museum, the late Dr. Albert Carl Ludwig Gotthilf Günther.

The latter named the fish Girardinus guppii in honour of my father, and this scientific label was employed long enough for its specific designation to be returned, by popular terminology, to its original form - Guppy.

Later on, after research by many scientists had been collated, the title Lebistes reticulatus was decide upon as being the best scientific term for the fish, but despite all this technical change Dr. Günther's original specific designation based upon my father's name, has continued in good standing throughout the world as the common name for the fish »; end of citation from http://www.tofino-bc.com/guppy/lechmere.htm.

Girardinus guppyi would remain until a revision of the Poeciliidae family took place in 1913, after which, Lebistes reticulatus have become than the scientific name. Oddly this last name is mistakenly still in use by several Internet sites today, even after been substituted by Poecilia reticulata long ago and happen to be presented in the literature only in older hobby books and publications.

During many decades this fish was regarded as a relevant biological agent and widely used to eradicate Malaria virus transmission mosquitoes from many tropical areas, owing to it believed larvae huge appetite.

Effectiveness of this as well as other species in biological combat against disease virus vectors like malaria, dengue, yellow fever or equine encephalitis are tested with regularity in tropical regions where these health problems are endemic.

Comparing with other alternative local species, when introduced as biological controller, Poecilia reticulata can become more or less successful, according to particular restricted conditions, but in any case can reveal to be supplemental to adjacent ecosystem mosquito larvae predators, due to it’s own biology and characteristics, ( Elmer Rojas et al., 2004 ).

Biological control techniques suggest some advantages above traditional chemical methods; above all where heavy and frequent rains fall rapidly dilutes the original concentrations of the products. Besides this possible occurrence, bearing in mind that larvae cycles take place every 7 days, chemical applications must be repeated weekly in order to assure usefulness.

By several reasons, biologic control is safer and more successful than traditional chemical methodology. The food chain isn’t dirtied by chemical devastating residual doses inside living things that increase effects from level to level and mosquitoes can’t develop immunity against predators.

Despite that, biologic control does have also some restrictions as well as technical hitches.

To achieve the expected results, biological control agents must be introduced in a huge number of effectives at targeted areas.

To penetrate in remote roughly inaccessible environments, like inside the dense vegetation, small fish are more adequate for the job. Even if they have actually no value as regarding human consumption, they can play an important role as they stand up in the nearly polluted waters where the insect sometimes put the eggs as well as larvae develops until free flight stage.

In addition to fish, there are a number of viable alternatives. Predator insects, aquatic carnivorous insects, carnivorous aquatic insect’s larvae, protozoan, fungi, bacteria and virus can be used to fight back mosquitoes in all of its live stages as well. The problem is that some of these alternatives are still under study and mass production along with manipulation isn’t as realistic as fish.

Nonetheless, secondary effects of new species introduction in each and every habitat must be a crucial concern, even if we are talking about such humanitarian aspirations like endemic highly lethal and incapacitating diseases inoculated by vector transmission mosquitoes eradication.

Last century Poecilia reticulata spreading world-wide in most tropical regions, especially as a biological control agent, was a very fashionable course of action implemented by governments and local authorities, since this species was considered a very effective larvivorous one. At present, many of consulted sources state that this is not the case in spite of everything, and a quite important number of scientists begin to support a contemporary view, according which the Guppy introduction represents little or even no effect at all, regarding mosquito control.

VI - Threats, protection and present status

Water contamination by domestic and industrial sewage can be regarded as an important threat faced by some Poecilia reticulata populations in some areas of its current geographical distribution.

The good news is that due to its existence in a vast area as well as in many tropical wild regions, more than ever after man made introductions, at least in a near future it’s not predictable that we can talk about any kind of serious danger upon this species.

By this reason, the Guppy conservation status is not an issue for concerning at the moment and it is not in the I.U.C.N. Red List.

For further knowledge or information about this please check Livebearer Cyprinodontiformes in the IUCN Red List of Threatened Species.

Other topics available about this species :

Literature cited ( references ) :

Alexander HJ, Breden F., 2004. Sexual isolation and extreme morphological divergence in the Cumaná guppy: a possible case of incipiente speciation. J. Evol. Biol. 17( 6 ) : pp. 1238-1254.

David N. Reznick, F. Helen Rodd, Michael Cardenas, 1996. Life-History Evolution in Guppies ( Poecilia reticulate : Poeciliidae ). IV. Parallelism in Life-History Phenotypes. The American Naturalist, Vol. 147, No. 3 ( March, 1996 ), pp. 319-338.

Douglas F. Fraser, James F. Gilliam, Jeena T. Akkara, Brett W. Albanese, and  Sunny B. Snider, 2004. Night feeding by Guppies Under Predator Release : Effectes on Grouth and Daytime Courtship. Ecology, 85(2), 2004, pp. 312–319.

Elmer Rojas P., Mário Gamboa  B., Segundo Villalobos R., Francisco Cruzado V, 2004. Eficácia del Control de Larvas de Vectores de La Malária con Peces Larvívoros Nativos en San Martin, Peru. Revista Peruana Med. Exp. Salud Pública 21(1), 2004, pp. 44-50.

John A. Endler, Anne E. Houde, 1995. Geographic Variation in Female Preferences for Male Traits in Poecilia reticulata. Evolution, Vol. 49, No. 3 ( June, 1995 ), pp. 456-468.

Poeser, F. N., M Kempkes and I.J.H. Isbrücker, 2005. Description of Poecilia ( Acanthophacelus ) wingei n. sp. from the Paría Peninsula, Venezuela, including notes on Acanthophacelus Eigenmann, 1907 and other subgenera of Poecilia Bloch and Schneider, 1808 ( Teleostei, Cyprinodontiformes, Poeciliidae ). Contributions to Zoology 74 : pp. 97–115.

Rojas J. E., Soca, L. A. and Garcia, G. I., 2005. Contenido del tracto digestivo de 4 especies de peces autóctonos y sus implicaciones como biorreguladores de larvas de mosquitos en Venezuela, 2004. Rev Cubana Med Trop, sep.-dic. 2005, vol.57, no.3

For further knowledge and better understanding on the Guppy issue please fallow this links :

Clube dos Criadores de Guppy do Brasil - http://www.ccg.org.br/ [ Portuguese ]

Guppy Brasil ( Rodrigo Ziviani ) - http://www.guppy.petbh.com.br/ [ Portuguese ]

Guppy Brasília ( Augusto R. Ewald ) - http://www.guppybrasilia.com.br/ [ Portuguese ]

Guppy Rio de Janeiro – ( Cherleston Chaves ) - http://www.guppyrio.hpgvip.ig.com.br/ [ Portuguese ]

Guppy Mendes - http://www.guppymendes.com/ [ Portuguese ]

Guppy New Zealand - http://www.guppy.co.nz/ [ English ]

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