Aquarium fish: Guppy (Poecilia reticulata)
Size: 6 cm
Origin: South America
Water temperature: 18-32 ° C
Aquarium volume: 54 l
Guppy (Poecilia reticulata ) – one of the best known and easiest aquarium fish to breed in the world. It comes in many different forms of breeding. Wild specimens are very rarely found for sale, commonly available come from commercial breeding or breeding farms. Unfortunately, many guppies available in aquarium stores are not so resistant anymore, and even susceptible to disease. It is best to buy fish from proven breeders who are passionate about the species.
In Third World countries, guppies were introduced by man to fight the infestation of mosquitoes, which carry malaria, and thus they acclimatized in many regions of tropical and subtropical climate zones.
Central America. It is native to the northeastern South America and the southern shores of the Caribbean. The original range covers An incredibly hardy species that lives in almost any aquatic environment, from high mountain streams to cloudy marshes and drainage ditches. Some populations are also found in brackish waters.
It probably thrives and thrives in habitats with abundant algae and vegetation growth.
Characteristics and disposition
The fish are clearly sexually dimorphic. The female guppy reaches 6 cm of standard length, has an olive gray body, and her anal fin is rounded. Mature females in the area of the anal fin have a dark so-called pregnancy stain. The male is slender, a bit smaller – it grows up to 5 cm and is nicer, more intensely colored.
There are multi-colored spots on its body, and the dorsal and caudal fins are elongated. Guppies also come in many breeding forms, with different fin shapes and colors. In trade, the “wild” primary forms are practically unheard of. They are very active fish, usually mild, but sometimes, mainly males, can nibble on each other or other fish from the upper parts of the water, and occasionally species with extended fins, such as angelfish. In the wild, they live in large groups, mostly females, and so should be kept in the aquarium.
In captivity, in a small space, males are very insistent towards females, they do not give them a moment of rest, while feeding, resting or giving birth. For each male, at least two females should be used. If we do not want to breed them, choose only one of the sexes for the aquarium, larger females or more colorful males. The small size of the guppies and their bright coloration make them an easy target for predators. In an emergency, they gather in a shoal.
Nutrition and feeding
In nature, they feed on algae remains, diatoms, invertebrates, plant fragments, insect larvae. In most cases, algae make up the greater part of their diet, but this depends on the specific conditions and the availability of food in the environment. For example, a study in wild Trinidad specimens showed that the diet of guppies collected in the upper Aripo River consisted mainly of invertebrates, while the specimens collected in the lower Tacarigua River region were dominated by algae (diatoms) and other mineral particles. In the aquarium, they should receive a variety of dry, frozen and live foods, e.g. waterfowl, daphnia, artemia, eyelash and plant foods, e.g.
dry with spirulina, blanched spinach, and lettuce. “Heavy” foods such as high-protein bloodworm should be avoided.
Despite its small size, for a group of guppies it is recommended to min. 54 l aquarium, with lush vegetation, also floating. The biology in a larger tank is much more stable, changes in pH are less violent, and the water temperature drops and rises more slowly.
The water for them should be rather hard 10-30 dGH, alkaline to alkaline in the pH range 7-8 at a temperature of 26-28 ° C. They also tolerate salinity well, because they are euryhalic species , i.e. they can tolerate different levels of water salinity, they can live in fresh, brackish (brachic) water, and even in sea water. Guppies will probably be best in a species aquarium or in the company of other beautifulls (e.g. gladioli, petals) and gentle cuirass that live at the bottom.
An alternative choice can be small rainbow or zebrafish. In a well-arranged and overgrown tank, they can also be combined with dwarf shrimps, but the smaller newborn ones can be eaten by them. Certainly, bad company will be e.g. fighters, spiked bellies, barbs, Siamese algae eaters or tetras who have a tendency to nibble on tetra fins, which, anyway, also prefer different water conditions. They will be food for turtles, crabs and crayfish.
Like most viviparous fish, breeding guppies is very easy . Due to the high spontaneity of males, there should be several females for each male in the aquarium. No special measures are required for reproduction, but lush vegetation is recommended, also floating, which will provide shelter for the fry. Guppies are very prolific fish. The gestation period varies, but is usually 21-30 days.
They usually breed all year round and females are able to fertilize again within a few hours after giving birth. Male guppies, similarly to other representatives of the Poeciliidae , have a modified cylindrical anal fin, the so-called gonopodium, located directly behind the pelvic fin. The breeding begins with courtship, the male insistently swims after the female, flexing his fins. If the female is susceptible, spawning takes place, during which the male briefly inserts a gonopodium into the female reproductive organ and fertilizes internally. The gonopodium through which the female milk transmits it has a canal structure.
Copulation is sometimes forced by the male. Interestingly, female guppies can store the milk obtained from the male for up to 8 months, which greatly contributes to reproductive dynamics in wild populations. The pregnant female has a dark spot under her abdomen, just behind her anal fin. The skin is translucent in this area and the eyes of small fish may be visible shortly before birth. Labor usually lasts from 1 to 6 hours, and the fish appear at certain intervals.
The female can give birth to 2 to 200 fry, usually 30-60 pcs. Well-fed guppies do not tend to eat offspring too much, but it is advisable to provide shelter. There are special breeding boxes available in shops, which can be placed in the aquarium. They provide a shelter for the pregnant female against too insistent males, and they also have a separate area for newborn fry, thanks to which they protect the fry from the female. However, caution should be exercised when using the breeding box, as a female placed in it too early may miscarry.
Often, well-overgrown aquariums already have enough hiding places for fry. The constant supply of adult guppies with live and frozen food, e.g. daphnia or artemia, can also reduce its losses. Young can be fed with artemia larvae, micro nematodes or nematodes, as well as ready-made powdered or liquid foods. In nature, two or three generations of guppies appear every year.
They are well developed and capable of living independently from the beginning. Young, gathering in a shoal, increase their chance of survival (avoiding a predator). The brood size may vary, but there are some constant relationships between populations, one of which is the degree of risk of threat from predators. Among females of similar dimensions, those in an environment with a high level of predation produce more numerous but smaller offspring. Females become sexually mature at 10-20 weeks of age and are fertile for the next 20-34 months.
Males are reproductive at about 7 weeks of age. The lifespan of guppies may vary, but is usually around 2 years. The body size of guppies is related to age, and their size during maturation depends on the predation in their environment. Males and females in high-risk areas for predation begin reproducing earlier than those in low-risk habitats. Females from high-risk areas are more fertile, reproduce more frequently and produce more offspring per litter.
Older females give birth to smaller offspring and at more frequent intervals. The mortality of guppies from high predation environments is higher, where there has been a significant increase in mortality among females at 6 months of age, while in low predation environments this does not occur until 16 months of age. However, due to their prolonged reproductive capacity, guppies in high-predation habitats have longer lives. After the reproductive period, no significant differences in their lifespans were noted. Food availability and density also influence the regulation of the guppy population.
In response to food shortages, they reduce fertility and reproduction, and when food is available, they increase the number of offspring. For example, during the rainy season from May to December, guppies from the northern area of Trinidad restrict reproduction, regardless of the level of predation. Density in a given environment is also important as greater intra-species competition causes a decrease in reproductive speed and somatic growth, and an increase in fry mortality due to cannibalism.