How to Breed Zebrafish

The zebrafish, also known as the zebra danio, was originally discovered in the rice fields of Eastern Asia. Since then, it has become a popular aquarium fish due to its hardy nature and curious disposition. Highly resistant to disease, the zebrafish is also extremely easy to breed in captivity. These small fish with distinctive stripes are such prolific breeders that they are commonly used in labs and schools for research; this also makes them ideal for the hobbyist who wants to try her hand at breeding.

Things You'll Need

  • Aquarium
  • Marbles
  • Brine shrimp or other microscopic food
  • Heavy cloth
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Instructions

    • 1

      Set up a proper aquarium. Zebrafish are not particular when it comes to their environment, so a simple glass aquarium with slightly acidic water will suffice. Add some vegetation to one area of the tank, and leave the rest open. Leave the bottom of the tank bare.

    • 2

      Introduce the school to the tank. Zebrafish do better in breeding when there are a handful of fish in the tank rather than just a pair. Make sure there are numerous males and females in the school. They are fairly easy to tell apart, as males are much smaller and thinner than females.

    • 3

      Begin feeding the fish a high-protein diet. Suitable food can be found at any pet store, and may include brine shrimp.

    • 4

      Prepare the tank by adding a layer of marbles to the bottom. Adult zebrafish will often eat their own eggs, fertilized or not. Using the marbles will allow the eggs to fall into the crevices between the marbles and keep them safe from adults. Drain and save the water until there is only a few inches left to ensure the eggs settle before they are eaten. Adjust the temperature of the water to between 78 and 82 degrees Fahrenheit, using a heater if necessary.

    • 5

      Cover the tank in the evening, being sure that any light is blocked. The fish should be kept in complete darkness for 10 hours to encourage them to begin mating.

    • 6

      Look in the tank for signs of eggs among the marbles. After two days, the eggs should begin to hatch. Do not feed the adults, because any leftover food can sink into the marbles and interfere with the hatching of the eggs.

    • 7

      Remove the adults when the first young begin to hatch. This can be anywhere from two to four days after the eggs are laid. Put the adults in a separate tank to prevent them from eating the fry.

    • 8

      Replace the old aquarium water in the tank once the fry are constantly swimming. For the first day of life, the young fish will typically remain on the bottom of the tank. They are not fully developed when they hatch, and once their bladders have developed they will begin to swim.