How to Breed Freshwater Rainbow Fish

There are many species of freshwater rainbow fish, and most are simple to breed because the males are usually easy to identify by their vibrant colors and longer anal and dorsal fins. The most successful way to breed rainbow fish is by using a separate breeding aquarium. The fish will breed in a community tank, but the results aren't as optimal because younger rainbow fish and other fish will eat the eggs. The size of the breeding aquarium needed depends on the size of the rainbow fish you are breeding. In most cases, a 14-gallon aquarium should suffice.

Things You'll Need

  • Aquarium
  • Gravel (1.5 pounds of gravel per gallon of water)
  • Marbles (optional)
  • Filter
  • Aerator
  • Java moss (can be purchased at many pet stores) or spawning mops (can be ordered online)
  • Fish food
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Instructions

    • 1

      Cover the bottom of the aquarium with a thin layer of gravel. Purchase the gravel from a pet store because gravel from a pond or river can introduce bacteria. You may want to purchase some aquarium marbles. The eggs will fall down in between the marbles and keep parents from eating them. Rinse the gravel or marbles in a sink with water before adding them to the aquarium.

    • 2

      Fill the aquarium with water and set up the filter and aerator per instructions on the box.

    • 3

      Wait 48 to 72 hours before adding the fish so the water temperature adjusts and the aerator can remove some of the chlorine and chloramine. Depending on where you live, you may need to purchase additional item(s) from the pet store to properly prepare the water. Ask someone at your local pet store whether there are any special needs for tank for your area.

    • 4

      Add some java moss or some spawning mops for the eggs to attach to and the fry to hide in. If you are using spawning mops, make sure they reach close to the bottom of the aquarium since many types of rainbow fish are used to spawning near the bottom of the tank.

    • 5

      Place a pair at a time or three male rainbow fish with two females when the aquarium water has adjusted. The fish should be similar in size. The fish will take over from here.

    • 6

      After the larvae hatch, which, depending on the species, can take four to 14 days, refer to them as fry. Feed the fry commercial fry food, liquid fish food or finely ground flakes often, but remove uneaten food quickly. As they grow larger, you can feed them larger-size food. It takes a few months for them to be fully grown.