If we asked the readers what their first pet was, surely many of them would answer that it was a fish. Among the most chosen aquarium fish as pets are Guppies, Platys, Xiphos and Mollys. One of the reasons why they choose them is their ability to reproduce. Known as viviparous aquarium fish, these fish give rise to fully-grown, self-contained live young and not eggs like most fish, which often gets people excited.
We invite you to continue reading this EcologíaVerde article to learn what are viviparous fish, examples and their characteristics.
Characteristics of viviparous fish
It is extremely important to clarify some concepts before starting to talk about the characteristics of viviparous fish. Many times people who are somewhat fond of the subject confuse viviparous fish with ovoviviparousand it is that, the fact that they give birth to juveniles and not eggs, generates confusion among the novices.
We briefly explain the difference between viviparous and ovoviviparous fish.
- viviparous fish: the embryo develops inside the mother, receiving nutrients from her through trophotaenia, a union similar to an umbilical cord. That is, there is a connection between the mother and the embryo, when it is already fully developed, the connection is interrupted and the mother gives birth to fully formed juveniles. so if you wonder what do viviparous fish eatfirst they do it through the mother and, later, they eat powdered food several times a day.
- ovoviviparous fish: here the embryos develop inside eggs that are in the internal cavity of the female. Here there is no direct connection between the mother and the embryo, but the eggs hatch inside the mother, so to the naked eye they look like fully developed juvenile fish.
Now that we have clarified the many, in this article we will talk about viviparous aquarium fish, a term used to refer to both true viviparous and ovoviviparous.
in these fish the type of fertilization is internal, the male has a structure called gonopodium or andropodium (depending on the family) which is nothing more than the anal fin modified for copulation. In some cases, the female can store the sperm inside her for several months and progressively fertilize herself without the need for a new copulation.
At the same time, most are omnivores and inhabit in freshwateralthough there are some that tolerate a wide range of conditions and can be found in brackish waters.
The most frequent families that include viviparous fish species are the following:
- Poeciliidae
- Goodeidae
- Anablepidae
Let’s take a closer look at some examples of viviparous fish. In addition, you may be interested in knowing more about the Reproduction of fish and the Life Cycle of fish in the following EcologíaVerde articles.
Guppies (Poecilia reticulata)
Fish of the poeciliidae family, its common name is due to the person who described it for the first time and they are true viviparous.
Males and females are different, the former are smaller (they do not exceed 3 cm), have a remarkable fan-shaped caudal tail, very colorful, and a gonopodium near the ventral fin, which is why they present sexual dimorphism. The rest of the body can vary in coloration but blue or silver predominates, while females are larger and with less variety of colors.
This species can be carrier of parasites and is believed to be responsible for the decline of several threatened and endangered species. It is also used in genetic researchfor example to eradicate malaria.
Molly (Poecilia sphenops)
They are also viviparous fish of the poeciliidae family. Is about calm and lively fish, in the wild they inhabit brackish waters and have even been found in the open sea. Although they are omnivorous animals, to stay strong and healthy, the vegetable fraction is very important and crucial in their diet. In aquariums they are usually the ones “clean” the algae from the bottom.
They are robust, measuring between 6 and 10 cm, the females are larger, the males longer, with more developed fins and a gonopodium. Are pale gray brown and silverfemales have dark spots on their body.
We tell you more about which animals are omnivorous: examples in this EcologíaVerde article.
Platy (Xiphophorus maculatus)
From the Poeciliidae family, if you see them in profile you will notice that the belly is more convex than the back. In addition they have a very large dorsal fin with spiny rays. They are yellow, orange, greenish or bluish, with a pattern of black dots. Males are smaller, more colorful, and have a gonopodium.
The males court females for copulation, displaying their fins and performing a dance. The type of reproduction is ovoviviparous and adults usually eat their young.
Mexican Carpin or Butterfly splitfin (Ameca splendens)
They belong to the goodeid family. They are silver to lead gray in color mottled with black, and the dorsal fin is further back than normalbeing at the height of the anal fin.
Males are less mottled than females and have a black and yellow stripe on the caudal fin. In addition, the first rays of the anal fin are modified into an andropodium. The females are viviparous, have 2 months of gestation and can give birth to 30 pupswhich are characterized by having visible trophotenias.
Xenotoca eiseni (Xenotoca eiseni)
Also known as red-tailed goodeids. present a somewhat rectangular body with a pointed head and the mouth up. The males are olive-colored with blue-green iridescence in some parts of the body. The females are all olive, with an orange tone on the caudal fin and a typical dark spot of pregnancy on the belly, they are viviparous.
Contrary to the poeciliids, the female needs to be fertilized through copulation at each reproductive event. Males have an andropodium as copulatory structure.
Halfbeak fish (Nomorhamphus liemi)
These viviparous fish of the zenarcopterid family have a very peculiar body structure. The body, head and mouth are long and thin and the eyes are above the end of the mouth.
They are light silver in color, with orange fins and a red and green line running the length of the body from the lower jaw to the caudal peduncle. At the ends of the fins they have characteristic black and red markings.
Also, the lower jaw is immobile, they only move the upper part when they look for food. In the wild they feed on insects and larvae that they catch on the surface of the water. The males are more colorful than the females and have a much more pronounced lower lip.
They are viviparous fish and parents tend to cannibalism, so in aquarium breeding it is advisable to separate them from their offspring. As they grow, the juveniles also become cannibalistic and feed on their smaller siblings.
If you want to read more articles similar to Viviparous fish: examples and characteristicswe recommend that you enter our Wild Animals category.
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