How to Breed Corey Cats

Corydora catfish are easy to keep and breed, even for relatively new aquarium hobbyists. Serious tropical fish breeders all have their individual styles and procedures for breeding these well-known scavengers, but it isn't rocket science. Cory cats are extremely accommodating when it comes to reproducing. You can succeed with this project without lots of fuss or tons of fancy expensive equipment. All you will need is a couple of tanks and a few minimal accessories.

Things You'll Need

  • 20-gallon aquarium
  • Mature sponge filter
  • Aquarium heaters
  • Spawning mops (optional)
  • 10-15 mature corydora catfish
  • Live brine shrimp
  • Live black worms
  • Live white worms
  • Frozen brine shrimp
  • Frozen bloodworms
  • Methylene blue
  • Tropical fish flake food
  • Fresh or frozen newly hatched brine shrimp.
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Instructions

    • 1

      Set up a bare 20-gallon breeding aquarium at least a month before spawning your cory cats. Fill it halfway with clean de-chlorinated water and equip it with a mature sponge filter, an air stone and an aquarium heater. Add two or three spawning mops, if you wish. Set the heater to keep the temperature between 70 and 74 degrees and turn the filter on. Don't turn the air stone on yet and don't put any gravel in the tank.

    • 2

      Add 10 to 15 mature cory cats to an established 30-gallon aquarium to condition them for breeding over the next month. They should be the only fish in the tank, if at all possible. Set the heater between 70 and 74 degrees and keep it at the same temperature as the breeding tank.

    • 3

      Feed the breeding candidates a protein-rich diet for four weeks to condition them for breeding. In addition to their regular diet, offer the fish live foods such as brine shrimp, black worms and white worms four times daily. Cory cats will also readily accept frozen brine shrimp and bloodworms. Proper conditioning will allow you to easily sex the fish for breeding purposes.

    • 4

      Choose four male and two female cory cats for your breeding herd. Look down at the fish to determine their sex. The male corydora is much slimmer behind the dorsal fin and more streamlined than the female. The females are larger and paddle shaped, with obviously more bulk behind their dorsal fins.

    • 5

      Move the breeders to your breeding aquarium and allow them to acclimate to their new tank for three days. Keep feeding them four times daily.

    • 6

      Add one gallon of room temperature de-chlorinated water or one or two trays of de-chlorinated ice to the breeding tank at night. The idea is to lower the temperate by two to four degrees each evening until it's 65 degrees. If one gallon of water doesn't bring it down at least two degrees, add a little more. If your cory cats are mature enough and properly conditioned, they will breed and spawn within a few days.

    • 7

      Move the adult cory cats back to their conditioning tank as soon as the females have finished laying their eggs. You'll know that they're done when they all go to the bottom of the aquarium to rest after spawning. If you don't remove them, they'll start eating their eggs as soon as they recover.

    • 8

      Add methylene blue to the breeding tank to discourage the growth of fungus on your cory cat eggs. Follow the packaging instructions carefully. Turn the air stone up as high as it will go. Increase the heat by two degrees every six hours until the water temperature hits 72 degrees. Maintain that temperature. In about five to eight days you should have several hundred baby cory cats swimming around.

    • 9

      Feed the new fry tropical fish flake food, or fresh or frozen newly hatched brine shrimp.