If you want to raise juvenile fish, it is best to know more about the pet fish you have, because raising juvenile fish is a very difficult thing.
Method 1: Determine the breeding method of fish
Find out if your pet fish is fetal or oviparous.
1) Fetal raw fish. Peacock fish, sailfin medaka, swordtail fish, and flower-spotted swordtail are the most common fetal pet fish. These fish will mate with males and females, after which the females will become pregnant. Usually after one to two months, the eggs hatch into small fish, and the females produce the small fish outside.
2) Distinguish between female and male fish. In general, protopnitotic males are usually more colorful than females, with elongated fins at the lower end of the tail. Females are greyish in color and have triangular or fan-shaped fins. If you can discern the sex of the fish, you can distinguish whether the two fish are fighting (usually between the same sex) or mating or preparing to mate.
3) Watch out for signs of pet fish mating. Pet fish can have mating, hugging and other mating activities depending on the species. For most pet fish, especially most silk-footed fish, the male will energetically chase the female, sometimes even tearing and biting. Fish such as the panlis will work together to guard their territory in the fish tank. In either case, when the male and female are copulating, the male and female fish will cling to each other, floating up and down, winding around each other, and some subtle small movements will also occur during this period.
4) Check the female for abdominal bulges due to pregnancy.
During pregnancy, the female will have a bulge in the lower abdomen. Within 20 to 40 days of a female's pregnancy, the abdomen becomes round or square. The pregnancy-related bulges of fish such as the spherical sailfin perch are further ahead than other fish, just below the gills. Obese males may also have bulges in the forebreast. If you stop feeding the fish for a few days, the male's bulge may become smaller, but the female's bulge due to pregnancy will not change.
See if the fish has produced red or black spots. Pregnant females have pregnancy spots, mostly concentrated on the abdomen or anus. These spots are usually black or bright red and become more pronounced as they grow during pregnancy.
Many fish have their own pigmentation spots, but these spots change in color as they enter pregnancy.
5) Decide what to do with the juveniles.
Raising juveniles or fry is difficult. Rearing juveniles requires a separate tank to prevent juveniles from being harmed by adult fish or filters. If you're not ready to raise juveniles, contact an experienced fish lover or aquarium shop and ask them to assist you or adopt juveniles.
Method 2: Pay attention to pet fish nesting and spawning
The following methods are suitable for oviparous fish. Many ornamental fish are oviparous, including the colorful angelfish, the fighting fish and most of the silk-footed fish. The spawns usually nest on the surface of the water, at the bottom of the tank or on the walls of the tank, and then lay their eggs in it. Males in the same tank will fertilize their eggs through ivory fertilization or mating. The eggs then hatch into small fish.
Some species of females can store sperm for months for later fertilization of their eggs. Therefore, even if the entire fish tank is a female fish, the pet fish may become pregnant.
Watch for signs of fish nesting. Some raw fish build nests to ensure the safety of their eggs. The appearance of the nest may be small pits or piles of gravel, sometimes very unremarkable. Some silk-footed fish can build elaborate nests with bubbles, usually built by males on the surface of the water.
Observe the fish eggs. Many raw fish produce an abdominal bulge due to pregnancy, but this change in appearance is not significant and lasts a shorter time. Fish are egg-shaped like bubbles that are scattered throughout the water, and some are attached to stacked nests or stuck to the bottom or wall of the tank.
Many oviparous fish fertilize their eggs by mating, including most silk-footed fish. During mating, the female and male are energetic and chase each other for up to several hours, after which the fertilized eggs are expelled from the female.
Prepare for hatching of fish eggs. Raising juveniles or fry is never easy, but you still have time to prepare before the eggs hatch. If you are interested in raising your own juveniles, you can contact the aquarium shop, as different fish are raised differently.
Method 3: Rearing juveniles
Raising juveniles or fry is no easy task, and you can ask the staff of the aquarium shop or the aquarium enthusiast online for information. The profession specializes, and consulting them can get more information than consulting a regular pet store.
Replace the filter with a sponge filter. If the filter in the fish tank will absorb water or produce water flow, please replace it with a sponge filter. Inhaled filters can exhaust juveniles and even suck them into the filter to cause death.
Separate adult and juvenile fish. Many fish breeders prepare a new tank and put the eggs or small fish separately. For owners with little feeding experience, it may be difficult to quickly create a suitable living environment for juveniles. You can separate the fish in the tank from the plastic nets sold in the aquarium. Some adult fish will take care of the juveniles, while others will attack the juveniles.
If adult fish protect their nests and juveniles after spawning, separate other fish from juveniles with nets and keep juveniles and males in one place.
If it is a fetal raw fish, or an egg raw fish that lays its eggs randomly in the water, separate the adult fish from the juvenile fish to prevent small fish from being attacked.
Juveniles are fed special feed. You can buy feed for juvenile fish from aquarium shops, but you have to choose. Ciliates, liquid fish food or rotifers are all good choices. As the juveniles grow, depending on the species, you may need to add additional fish food. Depending on the type of fish, ask the aquarium shop for information.
If you can't contact the aquarium shop, you can also squeeze the boiled egg yolks with gauze as feed.
Prepare the juveniles for growth. If you want to continue raising your pet fish, prepare a new tank for breeding. Otherwise, please contact the local aquarium shop or aquarium enthusiast, and the juvenile fish can be sold or given away after it has reached a certain stage.