Breeding aquarium fish is a rather laborious process, because in addition to the fact that the fish must receive the right amount of food, light and oxygen, it is necessary to determine the very fact of pregnancy in time and not to miss the birth of fry, which otherwise may simply be eaten.
Reproduction of fish, like any other animal, is a very complex physiological process, which is always accompanied by a number of features and which is influenced by the environment, both natural and artificial.
Fish that, after fertilization, are ready for reproduction, often need to be kept in special conditions, but for this it is important to correctly determine whether the fish is really pregnant. Each fish breed has its own characteristics, which are expressed both in a change in the color of females and in an increase in the abdomen.
Females of swordsmen are ready to mate already from 8 months, because it is at this age that these fish end puberty.
If a female swordsman is pregnant, a dark spot appears on her belly, and the belly itself takes on a rounded shape. Closer to childbirth, the tummy increases and takes on a square shape.
Such an aquarium fish as a guppy, which is also viviparous and very similar to swordtails, has its own characteristics of reproduction. To get pregnant, a female guppy does not need the constant presence of a male; this fish can throw fry several times from one mating performed.
It is quite easy to understand that the fish is pregnant: its sides and abdomen increase significantly. Just like in swordsmen, in guppies a dark spot is formed in the back, which increases in size closer to childbirth. Thus, the only difference between guppies is the repeated throwing of fry from one partner, and in swordtails, fertilization occurs once, and the female is immediately removed.
In the breed of cockerels, puberty begins at 4 months, a white spot becomes a hallmark of pregnancy for a female, and not dark, like in other fish, and of course, a rounded belly.
A feature of female cockerels is the process of birth itself: the male builds a nest from plants, and when the time comes he and the female freeze in this nest, then smoothly descend to its bottom, where the eggs are ejected. After that, the male protects the eggs for several days, from which the fry emerge, and then they are deposited, as well as the female who gave birth.
Bright and funny felling parrots are very popular today among lovers of home aquariums. These fish do not reproduce well, so they need special conditions. For example, for mating, the water in the aquarium is made warmer, and for throwing, a sink or shelter house is installed. Pregnancy of a fish is expressed by the usual signs - a swollen abdomen and a dark spot at the tail, but behavior also changes: the female increasingly tends to the bottom and leaves the light.