How to Breed Cory Fish

Corydoras catfish (or cory cats) are one of the easiest fish to breed in a home aquarium. Fish fry can usually be sold or traded to a local fish store once they are large enough and are eating prepared foods (such as sinking pellets and flake food). Control of the water parameters (pH, temperature, ammonia, nitrite and nitrate levels) is critically important for the health of the adult and fry corys.

Things You'll Need

  • 2 male cory catfish
  • 1 female cory catfish
  • 20-gallon aquarium with a large bottom surface area
  • Air pump
  • Air stone
  • Submersible heater
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Instructions

    • 1

      Add the air stone (attached to the air pump) to the breeding aquarium and turn it on. Fill the tank up with dechlorinated water, preferably water from the cory cats' home aquarium.

    • 2

      Fully cycle the water in the 20-gallon breeding aquarium. For best results, use the same water as the aquarium the catfish are coming from.

    • 3

      Add two males and one female cory catfish to the breeding aquarium. If the water parameters are different, remember to acclimate them slowly to the new environment. At this stage the water pH and temperature should be around 7.0 and 72 degrees Fahrenheit, respectively.

    • 4

      Add ice cubes made from dechlorinated water to the breeding aquarium until the temperature reaches 65 degrees. The lower temperature will trigger the cory cats' breeding. After a few days at this temperature the fish should lay eggs around the bottom and sides of the aquarium.

    • 5

      Remove the adult cory catfish after the eggs are laid. The sooner the adults are removed the fewer eggs they will eat.

    • 6

      Install the heater in the breeding tank and slowly bring the temperature up to 72 degrees. The air pump and stone will help create a gentle circulation in the water and help the heat distribute more evenly.

    • 7

      When the fish hatch, feed them live micro worms or live baby brine shrimp. They should hatch in about 10 days.

    • 8

      Change 10 to 20 percent of the water in the fry tank every day. Fry are very dirty and leave a lot of leftover food, which will cause a dangerous spike in nitrates. High nitrates will kill the fry. By replacing the old water with freshly mixed and dechlorinated water you remove much of the nitrates.

    • 9

      As the fry grow, feed them larger foods, including flake and pellet food.