Kingdom   Animalia

Phylum     Chordata

Class        Actinopterygii

Order        Cyprinodontiformes

Family       Poeciliidae

Genus       Poecilia

Species     Poecilia reticulata

Guppy Basics

The guppy species is a small South American-origin tropical fish that is currently widespread worldwide. This is also one of the most common species found in freshwater aquariums. Males are distinguished by their brilliant and ornate caudal and dorsal fins. This species is used widely as a model animal in several academic areas, including ecology and evolution.

Guppy Description

Guppies are little fish. Males measure only 0.6–1.4 inches (1.5–3.5 cm) in length, far shorter than females. Females are about double the size, measuring 1.2-2.4 inches (3-6 cm) in length. Males are also more colourful and ornate, with females lacking decorative fins.

Guppies in captivity have been exposed to extensive specific breeding due to their popularity as a freshwater aquarium species. As a result, several strains have emerged, each distinct in terms of colour, shape, size, and pattern. Guppies in the wild are usually less colourful and smaller than domestic variants.

Guppy Range and Habitat

The species was first reported in 1859 and 1861 in Venezuela and Barbados, respectively, and is now found in many additional Caribbean nations and northern South American countries. They are a species endemic to warm areas near the equator and are hence tropical. They have been brought to many regions of the globe since their discovery. They have spread to all continents with the exception of Antarctica.

Guppies have invaded almost all the freshwater environments in their native range. They’re very common in streams towards the seaside. Within this region, they prefer smaller streams and ponds over bigger bodies of water. This includes brackish, very salty waterways, which they have colonised and inhabited despite not being normal habitats. Guppies, like the molly (Poecilia shphenops), a similarly related fish that likes saltwater settings, may adjust to it if required.

Diet and Predators

The guppy eats a range of things in the wild, including algae and debris. Mineral particles and tiny invertebrates like miniscule shrimp-like organisms will also be consumed. They also eat mosquitoes, notably their larvae, which are frequently deposited in lakes in which guppies flourish. Guppies find food in clusters and use a community system to alert one another of predatory dangers. This permits each individual to spend less time looking for predators and more time eating.

Guppies are prey for a variety of species since they are small fish. Guppies of all sizes are easily consumed by larger fish. The blue acara is a frequent predator of guppies in the wild (Aequidens pulcher). Guppies are also prayed for by many birds.

Reproduction

Guppies in the wild are very prolific, with females producing two to three generations every year. Unlike many other fish species, guppies do not deposit eggs; they give birth to live young fish that are self-sufficient from the moment they are born. To avoid predators, young guppies will establish schools. They are, nevertheless, very fragile due to their tiny size.

During each breeding season, females will mate with many men, a mating practise called “polyandry.” If successive partners are more beautiful than the first, they will even postpone the growth of their brood. Females may retain male sperm in their ovaries and gonoducts for up to eight months. The gestational period for every offspring is typically three to four weeks, but varies widely according to external factors like temperature. 

These offspring will reach sexual maturity between 10 and 20 weeks for females and 7 weeks for males. Guppy longevity varies greatly depending on natural conditions, including the quantity of predation they encounter in their specific area, But in the wild, it is normally just 2 years.

Fun Facts about Guppy

There are many intriguing things to learn about the guppy. It may be found on almost all continents and is a popular species for research study and household aquariums.

The Great Mosquito Colonizer

People will ask how the guppy, a small and seemingly boring fish, managed to populate the healthy environment and millions of people’s aquariums. In fact, the bulk of species introductions were inadvertent, perhaps as a result of badly handled ship bilge water, which may have moved animals and larvae to new habitats across oceans. In many places in the world, however, the guppy was intentionally established as a method of pest control.

Governments really imported guppies in well-intentioned but largely unsuccessful and frequently disastrous efforts to manage local mosquito populations and illnesses like malaria. However, when non-native fish are brought into new settings, there are often unforeseen ecological repercussions. In locations where it has been introduced, the guppy may be found in almost all freshwater ecosystems. This is fantastic news for the guppy population. Guppies, on the other hand, have already outcompeted indigenous fish in several regions where they have been introduced due to their flexibility.

Sexual Dimorphism in the Guppy

In birds, sexual differentiation is widely established and acknowledged. Males are usually bright and showy, and they create habits and activities, such as courting dances, to emphasise these characteristics. These phenomenon of different physical looks across species, however, is ubiquitous in the animal realm and happens in fish, such as the guppy.

Females are important in sustaining the flamboyant fins and colours of males. They prefer the males with brighter colours, notably those with orange side markings. This exerts a selective constraint on male populations of guppy, favouring those with orange markings, which may indicate foraging skill and general health. However, in the wild, this vivid pigmentation might make males more visible to predators and hence more likely to be eaten. Thus, it is an evolutionary trade-off. Males will also engage in courting displays like those seen in many birds, twisting their bodies into an S form and rapidly vibrating while flapping their intricate fins in the stream.

A Model Specimen

The guppy has frequently served as a model organism for ecological studies, evolution, and other fields, owing to its low death rate in captivity. Guppies have 23 chromosomal pairs, along with a pair of sex chromosomes, which is unusual. This is also true in people, making them ideal candidates for genetic investigations with implications for human health.

It has been shown that the life histories of guppy populations living in a variety of habitats with varied environmental stresses, and strains are adaptable. Guppies, for instance, will devote more time and energy to generating young in places where predators are more prevalent. In regions where there are no predators, they will develop quicker and begin breeding sooner than guppies. Additionally, they will breed more often and produce larger broods than guppies in less stressful situations.